Dosing for 500G aquarium - The Planted Tank Forum
 
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post #1 of 15 (permalink) Old 01-19-2010, 04:51 PM Thread Starter
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Dosing for 500G aquarium

I need a starting point for creating a dosing regime for a 500 gallon aquarium. The aquarium will have medium to high light, pressurized CO2, and will probably be medium to highly planted.

I've looked at the EI method, but a 50% water change on a 500 Gallon aquarium every week would be nearly impossible, and expensive, even if I automate the changes. I'm considering daily 5-10% automated changes.

Fish load will not be very high. We're looking at a few very colorful fish and some red cherry shrimp.

What I'm looking for right now is a starting point that I can adjust up or down as needed. Most of what I've seen on here seems to be more geared to smaller aquariums though.
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post #2 of 15 (permalink) Old 01-19-2010, 05:55 PM
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There are many ways to approach this, here is what I would do...

You are correct in that 50% water changes for a tank this size are not really justifiable. Even if cost isn't an issue, for a tank this size rather than using excess fertilizer and diluting that with fresh water it might be better to do a bit more calculating. (Keep in mind when you say daily 10% water changes this would add up to something like 50% though).

Every tank is different, so it will be impossible to give exact values or teaspoons. One starting point would be your tap water. What's in it? Some contain already sizable amounts of NO3 and PO4.

It might be good to invest in a Nitrate (and perhaps Phosphate) test kit, to monitor the dynamics of your tank, at least in the beginning. While you know how much a certain amount of powder will increase levels, testing will tell you what you are at and how much is used up in a given period. For larger tanks, this might be less than you'd expect (compared to a 10gal jungle type tank for ex).


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post #3 of 15 (permalink) Old 01-19-2010, 06:15 PM
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I agree with wasserpest to monitor the levels of nitrogen and phosphorus instead of doing EI dosing and the impractical 50% water change on a 500 gallong tank. Just keep the levels of Nitrogen and Phosphorus at desired range.


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post #4 of 15 (permalink) Old 01-19-2010, 06:15 PM
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Why dont you try PPS-PRO. Here is a link to the guide.

It works for me and you dont have to do as many WC's.

What are the tank dimensions?
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post #5 of 15 (permalink) Old 01-19-2010, 06:24 PM Thread Starter
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Tank's dimensions are 10' x 32" x 32" with overflows in each rear corner.

Tap water here is river water and there is a lot of farmland in the area so I suspect, though I haven't tested, that phosphate and nitrate content are rather high.

Wasserpest: On the water changes, would I be better off doing smaller daily changes, like between around 2% or something?
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post #6 of 15 (permalink) Old 01-19-2010, 06:48 PM
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Why dont you try PPS-PRO. Here is a link to the guide.

It works for me and you dont have to do as many WC's.

What are the tank dimensions?
Yeah, I definitely say go with PPS. PPS is IDEAL for large tanks. You can go a long time without water changes using PPS, but even still I generally do them every two months. 50% every 2 months, or 25% once a month is probably fine.

What wattage are you considering for that bad boy?


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post #7 of 15 (permalink) Old 01-19-2010, 07:05 PM Thread Starter
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What wattage are you considering for that bad boy?

I've got two fixtures that use 6 F54T5/HO bulbs, so a total of ~ 648 watts.
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post #8 of 15 (permalink) Old 01-20-2010, 06:06 PM
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I would think that one of the biggest issues using river water would be source values. If you were to start the tank in winter your base nutrient levels might be quite low. Then you get into a certain fertilizer regime. Then summer comes along and farmers start fertlizing. I have seen water N03 levels here (large area of hay fields) get up to 42 ppm. That would mean you would need much less NO3 dosing. If you were using an automated system, you might not notice the change. Those kind of base N03 levels, plus large doses of nitrate could end up with fish toxicity.

I think no matter what whaterchange/dosing strategy you use, regular(monthly?) water testing would be advised.
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post #9 of 15 (permalink) Old 01-20-2010, 07:34 PM
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Quote:
Originally Posted by BrentD View Post
I need a starting point for creating a dosing regime for a 500 gallon aquarium. The aquarium will have medium to high light, pressurized CO2, and will probably be medium to highly planted.

I've looked at the EI method, but a 50% water change on a 500 Gallon aquarium every week would be nearly impossible, and expensive, even if I automate the changes. I'm considering daily 5-10% automated changes.

Fish load will not be very high. We're looking at a few very colorful fish and some red cherry shrimp.

What I'm looking for right now is a starting point that I can adjust up or down as needed. Most of what I've seen on here seems to be more geared to smaller aquariums though.
This means 35-70% weekly water change if you do this daily, and the remixing makes this process even less efficient than one single large water change.

If you simply dose, monitor some, then do say 25% weekly water changes, or 50% every 2 weeks, this works easily.

You can easily dose and adjust to suit this way.
I go 2-4 weeks on many tanks without water changes by watching.

You slowly reduce the upper levels of dosing(the ones you know are non limiting) till you get a negative effect on plants.

So say you dose 2 table spoons 2-3x a week of KNO3, try 1.5, then 1 table 2-3 x a week. Try each new reduced value after 2-3 weeks, while you will do more water changes until you dial this in well, the long tern result will be easier.

You can test, but I'd suggets a good test kit and calibrate the then with reference solutions, if you do not do that, you might as well go back to doing water changes, because you will be guessing otherwise.......

Since you are planning less labor and water changes, do yourself a HUGE favor, dial the dang light intensity down.

That is your 1st mistake, more light is not better.
Why limit water changes, nutrients or CO2, when you do not do this for light?

Plants simply do not need that much light.

Light drives CO2 uptake which also drives nutrient uptake/demand. So by using less light, you use less nutrients, less CO2 demand, less algae growth/issues and .......less water changes are needed.

You also have less growth and weedy trimming to do, so less labor all around.
The same approach to nutrients and water changes I would suggest you also do for light.

Get or borrow a light PAR meter and test the light and see.
Look, light is far more stable than CO2/nutrients can ever be, so work with less there and everything else will be much easier.

I use about 1.7 watt/gal of T5 lighting on most tanks and even there, I raise the lights up about 12-16" inches, shooting for about 40 micrmols of light at the sediment.

Speaking of sediment, using enriched sediments, soils, ADA As etc will allow you more wiggle room with dosing and reduced water changes after the first 1-2 months.

It adds a redundant back up source for nutrients.

So there's a few things you can do to avoid water changes, I still do them since I do not like to have a snorkel mask on when I clean the aquarium, 500gallon tanks are not shallow, so you have to drain some water to work on them. EI is not meant to followed blindly and strictly, it's just a point where you can know there's little chance of being limited for N, P, K, or traces.

Leaving them high does no harm anyone has ever shown.........but then again, there also no need to let them build up very high either.

Here's a 350 Gallon(400 gal total) example:



Runs about 1.9 w/gal at 18" height above the tank.
Another:

1.8 w/gal:



etc.........


Regards,
Tom Barr




Regards,
Tom Barr
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post #10 of 15 (permalink) Old 01-20-2010, 07:46 PM
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I've got two fixtures that use 6 F54T5/HO bulbs, so a total of ~ 648 watts.
This likely about right.

3x 54 per 4ft length and an 8 ft long tank?
Make sure they are widely spaced apart.

BTW, PPS does not provide non limiting nutrients for many aquariums, so you need to fiddle with it and add more, add more PO4 etc, so like EI, you adjust it to suit.

And as far as CO2, it is a function of current, so make sure you use more current, eg, a Vortech MP40 would be wise and provide a lot more current per watt of energy used.

This mixes the CO2 and makes the filtration work much better with less gph.
Most who claim higher CO2 causes them issues have low current and gas their fish due to low O2(just like a normal tank without plants, and adding a bit of CO2 gases them to the surface since they where already stressed due to low O2.

You can easily add a bit more CO2 for the increased current loss of CO2 to the air. You cannot add life back to a fish that's dead.

Good O2 provides the best defense for CO2 and fish issues.
Testing CO2 is dicy, it's not easy for anyone, so beware folks claiming they have 15ppm of CO2, or 28ppm CO2.

They likely do not and CO2 is the most variable parameter in the planted aquarium, it can move minute to minute and hour to hour.

Focus there. I think you light is good so there will less issues for CO2 and dosing. Realize a fully planted mature tank will use more nutrients and be much more stable than new tank, so more water changes are typical during the start up phase.

ADA also suggest large water changes as do I, but folks can get away with monthly water changes and some experience with any method.

It's a myth to assume otherwise
Weekly is just a suggestion, ADA suggest that also.


Regards,
Tom Barr




Regards,
Tom Barr
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post #11 of 15 (permalink) Old 01-20-2010, 07:46 PM
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I don't know if you've had planted tanks before, but I would definitely plant in a way that you don't have to do much near the bottom. I would plant alot of lowlight plants on wood, etc. (like the Barr tank in first pic) that can be trimmed easier and don't require heavy dosing. If you put fast growers in, let's just say it will not be 'fun' to trim and fine-tune the tank with that depth.
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post #12 of 15 (permalink) Old 01-20-2010, 08:39 PM Thread Starter
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Tom, thanks for the advice. I realized after I had already posted that the daily 10% water changes were probably more excessive than I intended. Some details on my tank can be found in this thread: Big Project Pics are on page two of that page. It's got two circulation loops. One that runs 2 sumps and another that just circulates water from the center of the tank through a carbon canister and back to a drilled T-Pipe that runs along the bottom rear of the tank. I'm planning on removing the carbon canister from the second loop and using that loop as my injection point for ferts and CO2.

theredben: I'd already thought about the nutrient inconsistency of the river water. To make matters more interesting, we have 8 sewer plants upstream from us who all dump their treated water back into the river.

Whatever I do I will end up doing a lot of water testing. I'm planning computer control of all the automation. Will probably end up using an adjusted PPS-pro method, and may separate NO3 and PO4 into individual solutions so I can control their dosing independent of other nutrients.

I wish there was an electronic way to test of NO3 and PO4... That would make life a little easier. :P

One other little fact that I Just remember that is probably relevant: There was an article in the local paper recently about our city water system and one of the things that they mentioned was that the water department had been adding ammonia to the water to stop corrosion or something, but they stopped doing that because there were too many complaints about the smell.
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post #13 of 15 (permalink) Old 01-20-2010, 10:00 PM
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Tom, thanks for the advice. I realized after I had already posted that the daily 10% water changes were probably more excessive than I intended. Some details on my tank can be found in this thread: Big Project Pics are on page two of that page. It's got two circulation loops. One that runs 2 sumps and another that just circulates water from the center of the tank through a carbon canister and back to a drilled T-Pipe that runs along the bottom rear of the tank. I'm planning on removing the carbon canister from the second loop and using that loop as my injection point for ferts and CO2.

theredben: I'd already thought about the nutrient inconsistency of the river water. To make matters more interesting, we have 8 sewer plants upstream from us who all dump their treated water back into the river.

Whatever I do I will end up doing a lot of water testing. I'm planning computer control of all the automation. Will probably end up using an adjusted PPS-pro method, and may separate NO3 and PO4 into individual solutions so I can control their dosing independent of other nutrients.

I wish there was an electronic way to test of NO3 and PO4... That would make life a little easier. :P

One other little fact that I Just remember that is probably relevant: There was an article in the local paper recently about our city water system and one of the things that they mentioned was that the water department had been adding ammonia to the water to stop corrosion or something, but they stopped doing that because there were too many complaints about the smell.
As far as automation and testing, this requires a lot more work and details and management than you might think.

There is no automation for NO3/PO4.
So that's manual testing and is a PITA, if you plan on using the data for any dosing, you will have to calibrate the test and make sure they are correct, just like using a pH meter and a 2 point reference with 4 and 7 pH's.

So you will need a a set of reference solutions for the NO3, I'd not even worry about PO4 testing unless you plan on using strict PPS, in that case, you'll end up with a lot of GSA on the glass and plants, and at 500 gallons, that will be a PITA.

So modify the dosing for 3ppm for PO3 and about 20ppm for NO3 as targets.
These will float and move around so here or there, but as long as they are in those general regions +/- 40% or so, things will be fine.

CO2 is far more important and will be a MUCH larger issue, EI/PPS, they both add the same things, one is richer, the other is hold over from PMDD days and leaner.

So adding more of one is the same as adding less of another.
How you get there does not matter to much.

If you want to adjust the dosing, you can use water changes, easy, fast, no testing or uncertainly there.

Or you can use test kits and adjust according the those and do less/few water changes, that is the trade off. PMDD suggested this as have I in the past. EI evolved from PMDD and PPS is almost identical to PMDD and while not cited, obviously took nearly all other than the PO4 limitation part for the dosing method. Not like I have not done both for long time.

There is no magical method that avoids both test and water changes and still keeps the dosing the same.

Adding enriched sediments would be close to that, but even there, you still have to dose. A non CO2 method would be as close to the no test, no water change methods, but it seems you like CO2/techy stuff, so I'll assume that is your goal.

I'd avoid the mythical fully automated everything, that's justr askign for systems failure and more work in the long run.

More nick nack to go wrong, dump in way too much nutrients all at once, pH probe breaks, falls out, kills the tank etc. Simple, hard to break, and good routine maintenance will go much farther.

Also, while you might have a lot of motivation right now, testing gets really old really fast. I have more experience testing water than most ever would like to say they have. Few hobbyist with 5-10 years of experience bother testing week to week, few even month to month, most do not after a bit.

Folks nag you to test but often do not do it themselves.

The tanks I do have not been tested, some have for a time by their owners, they always stop after a time though and realize it's not required once they get some experience, know what to look for and watch their tanks and do not neglect them.

Dosing is only a small part of this, CO2 and light is 90% of it. You sound like the light is in good shape, so most of the issue now will be CO2 and mixing.

Seal the sumps up(duct tape the dry sections so that no air/gas can exchange) and raise the overflows so they only drop about 2", add a hofner grugle buster(search google etc) to each.

This will eliminate most of the CO2 loss from the sumps.
I'd just feed the CO2 into the return pumps or use a fine stone to feed them to reduce the impeller noise as the CO2 hits.

Unlike many folks, I have a long historty with large tanks in this size and a few orders larger. Management is not the same as simply using nutrients to magically solve all your problems, many imply that, it's simply not the case.
You must look at the big picture.

Otherwise you end up with a huge mess, lots of labor and time spent on the tank and the cost goes way up then. I'm glad you have the light you do on this tank, that's one saving grace.

CO2/current will be your nemesis, nutrients will be easy.

I'd suggest you read Left C thread on CO2 dual stage regulators and get the best CO2 reg, needle valve and solenoid you can. I have used mass flow controllers from Alicat, CO2 meters from Oxyguard etc.
These are 1200$ and 3000$ each.

I do not think those are practical here, but a good reg, good needle valve (Nupro 's SS 1/8" with a vernier caliper handle makes adjustments incrementally far easier).

Just go slow and methodical with CO2, do not get impatient, do not adjust and then wander off for the rest of the day, watch the tank closely when you adjust the CO2. Do not get gun shy with CO2 either if you go too far.
Good current will save you and make it much easier to manage without any issues.

Good plant selection and scaping will also make the result look much nicer and easier to care for. Chose plants that are easy to grow and grow on wood etc.

Amano did this for his large tank, as did I with the tank above and with this tank:



This client suffered since the sediment is plants and it's 4ft deep.
But, he does not bother testing or spends much time on dosing, he has a hard plumbed tank so drain and refill is easy. Water is cheap, testing and labor is not.

All he does is turn a valve to drain(10 minutes), and then shuts it off and turns another to refill. Since the tank is deep, you have to drain it down to get in and work on it.

He does a water change about once every 2 weeks, sometimes longer now.
So the water change is perhaps the easiest part, and it does not cost more than shower or two extra a week's worth of water. That's 1$ at the highest water prices in CA which are some of the highest in the USA for this 1600 gallon. Since it's hard plumbed, it also involved no labor or testing.

He also suffered due to high light disease (HDL). Now the tank is light limited, around 25-30 micromol at the bottom. You tell these folks what to do, but they think they know it all. So you let them suffer till they give up and try it your way.

hahaha

This is my version at the 60 gal scale:



Very easy to care for, I change the water 2x a month, never test, these fish have been in here for 3 years now.

Regards,
Tom Barr




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post #14 of 15 (permalink) Old 01-20-2010, 10:10 PM
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Keep in mind that there are many ways to do things, and often what works great for one doesn't work for another. That's the fun part with planted tanks.

Personally I think with tanks this size it is better to do "smaller" daily water changes than big ones every month or so. Of course, like I said, someone else might experience just the opposite.

I currently do very small water changes on my 250gal tank, still dialing in fertilizers and such. Daily water changes of 5gal. I plan on increasing them to 10gal per day, which is still comparatively small, nowhere near 50%.


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post #15 of 15 (permalink) Old 01-20-2010, 10:55 PM
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I think there is a good argument for doing large % water changes since the dilution and remixing rate is much less, TFH has an article recently presenting the infinite series argument mathematically illustrating that.

It takes me relatively the same motivational effort do a WC so if I bother, I'm going to go big.

For smaller amounts, I think you are good with the infrequent factor of water changes, I do not suggets going too big unless the tap and tank are somewhat similar. This is fine if you do them often, but if you do WC's once every 2-3 months, go 25%, not 80% etc.

Then the next week, maybe 40%, and then 50%.

If you stay on top of them, you can do 90% water changes with no ill effect, then your accuracy is as good as most any test kit since 90% of the make up is basically a reference solution.

Hard plumbing is the only way to go for larger tanks, makes any of this far easier and virtually no labor or cost, drain and refill in minutes/hour or so.

I spend all of 1.5 hours a week on a 350 Gal tank. Cleaning, refilling this or that, restocking things, trim, cleaning the glass, everything. Drip dosing worked the best. Fill with regular water to make sure the rate and dosing works right and come back and week later to make sure the total volume dosed is still good.

Only then do you add the fert solutions.
And then only a week's worth, that way there's less chance to over dosing should anything fail.

It's packed with fish and I pulled some red farowellas, corys fry of the tank 2 weeks ago that bred in there.

Still, I think there's good arguments for small % water changes and larger %.

However, water changes never hurt a planted tank unless perhaps it's a non CO2 system. So doing good water changes is a wise simple method that is at the basis for the entire aquarium hobby.

Regards,
Tom Barr




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