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post #1 of 19 (permalink) Old 12-03-2003, 02:24 PM Thread Starter
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I just added pressurised co2 to my tank at 6 bubbles/min (180L Tank). This pushes my pH down to 7.2 (from ~7.5). By using a water softener pillow my dkH goes down to 12 (from off the chart). According to Chucks calculator this gives me a co2 level of 23ppm.
Does this mean I can't add more co2 to reduce my pH to more discus friendly levels without killing everything ?
And if the pillow fades (which it does - needs recharging with salt every 48 hours, and I usually forget) my kH will increase to toxic levels.
This also means that my water out of the tap (faucet ?) contains a co2 concentration of over 24ppm.
Is this right ???
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post #2 of 19 (permalink) Old 12-03-2003, 04:09 PM
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It could be. But you need to check the tap water pH after it has rested for a few hours to let the dissolved gases dissipate. You can run your CO2 as high as 35 ppm with no harm to your fish as long has you have good O2 levels in the tank. With your water I'm hoping that you either have a controller or are running the CO2 24/7 to avoid pH swings. Why not get a couple of pillows so you can just swap them out. But the thing that concerns me is all the sodium you are adding to the tank using those pillows.
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post #3 of 19 (permalink) Old 12-03-2003, 07:01 PM
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I don't think you are really helping much with the water softener pillow, you are just trading minerals that are a part of the KH measurement for minerals that are not a part of the KH measurement.

You may find that you need an RO system to really get the water pure enough for discus to breed.
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post #4 of 19 (permalink) Old 12-04-2003, 08:24 AM Thread Starter
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I left some tap water out last night that I will test tonight for kH, gH and pH.
If all the results are really that high, is additional co2 necessary ?

----
I keep the co2 running 24/7, along with a small airstone, at some point I will put the airpump on a timer to run during lights out - is this good ?

I'm not planning on breeding the discus just yet. Maybe in the future.
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post #5 of 19 (permalink) Old 12-04-2003, 09:32 AM
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Quote:
Originally Posted by tombsc
This also means that my water out of the tap (faucet ?) contains a co2 concentration of over 24ppm.
Is this right ???
I doubt it. A small measurement error in either KH or pH can make a noticeable difference in the derived CO2 levels. Matching colors on a chart can always introduce a little error in pH measurements. If you're titrating your KH (add one drop at a time until you see even the slightest color change) then that's a more accurate number than your pH (if it is a match the color test). If you're using a calibrated digital pH probe and a KH titration test then maybe you do have that much CO2. If it really is CO2, then running an air stone in a jar of sample tap water for a few hours should drive out the CO2 and show a noticeable change in pH on a second test. A CO2 titration test kit might be worth considering in your situation to confirm what's going on. Lamotte makes a very good (but somewhat expensive) CO2 titration test kit. The initial kit purchase is rather expensive, but the refill test chemicals are inexpensive so the big investment would be in the initial purchase of the kit.

On the low-tech "visual test" side - if the plants are pearling nicely and the fish aren't gasping at the surface, you probably have your CO2 set about where it needs to be.


I can sympathize with your plight. Trying to get the pH of very hard water down to something that Discus will prefer can be difficult and expensive. Unless you are a more discliplined person than I am, you will find yourself putting off doing water changes because of all the fiddling you have to do with the water and the cost of the chemicals you'll use to get the replacement water where it needs to be. An RO unit with a big holding tank for the RO water (and a heater to keep the RO water at aquarium temperature) will make life a little easier for you (and less expensive in the long run). With RO, you can develop a "formula" for reconstituting a known amount of RO water to the KH/pH you want fairly easily. "Recon-50" or "RO-Vital" can be used to reconstitute the RO water. Then "Discus Buffer" or "Acid Buffer" will get the pH down in the range Discus prefer. This approach would make good "breeding water" as well.

If you use your tap water, you would only add "Discus Buffer" or "Acid Buffer" to it, but you'll need a lot more of either. You'll also need to watch for the pH to rebound to a higher level several hours after you add the acidifier (because of the high buffering capacity in your tap water).

In any event, I don't think you will be able to lower the pH enough with CO2 alone without stressing your fish. You'll probably need a combination of some kind of phosphate free acidifier (like the ones mentioned above) to get you closer to the target pH and then come down the last little bit with CO2.

The good news is that unless you want to breed the discus, the KH doesn't really matter so much... just the pH.

Good luck!

Tim

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post #6 of 19 (permalink) Old 12-04-2003, 01:27 PM Thread Starter
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Many thanks for that info Tim.
FYI I use a pH kit from Hagan where I add 2 drops of test solution to 5ml of tank water and try to match the colour against a chart. The kH measurement is from a dry tab dip test.
I guess neither are very accurate but the best I can do.
I will buy a co2 permanent test this weekend (thats all I can find around here (£15)) and see what it says, I will also post my tap water results here tomorrow.
The fish aren't gasping yet, but I still have the airstone running.
The plants seem to be growing faster and greener since the co2 addition, but not pearling - in fact the hairy algae seems to have increased a bit.
As for RO - way out of my league - too expensive and I wouldn't have room to store the water anyway !
Btw, I really am an algae grower - did my thesis on marine red algae, and the carpet of lush green algae I have in my Mbuna tank pearls beautifully ! :lol:
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post #7 of 19 (permalink) Old 12-05-2003, 04:05 AM
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Quote:
Originally Posted by tombsc
The fish aren't gasping yet, but I still have the airstone running.
The plants seem to be growing faster and greener since the co2 addition, but not pearling - in fact the hairy algae seems to have increased a bit.
Your CO2 test kit should be quite helpful. If you can get enough light, enough CO2 and enough nutrients to get the plants to pearl nicely, the plants will do a very good job of oxygenating the water. I've learned never to say "never"... but I will say that I don't think you'll find your airstone necessary at all in a well planted tank - especially one with CO2 injection (that should make the plants produce lots of oxygen).

For peace of mind with respect to your CO2 levels and the necessity for the airstone, I believe your fish will tell you if they have too much CO2 or not enough oxygen. If you see them staying near the surface "gulping" air, then something is amiss. I had a pH probe whose calibration had drifted significantly over a long period of time - so the CO2 controller kept adding more and more CO2 as the probe drifted more and more out of calibration (towards the alkaline side of the spectrum). One day I noticed the fish were intermittently gulping air at the surface and tested the probe. After re-calibrating it, the fish behavior returned to normal within an hour or two.

I keep my CO2 level at about 30 ppm (I have found it as high as 35) with no ill effects to the fish. This concentration was determined with the CO2 test kit as opposed to computing CO2 from the pH and KH. I don't use any airstones or anything else that will disturb the water's surface and promote CO2 loss.

If your algae is still winning the nutrient competition, then it is likely something else is still deficient... either not enough light or still not enough CO2 or a nutrient imbalance caused by 1) some nutrient in short supply that the plants need that the algae can get by without or 2) some nutrient that is overly abundant (most likely culpret here is phosphate).

I don't recall what your lighting parameters were, but if you are in the 2.5 to 3 watt per gallon range, that should be about right. With your CO2 test kit, you can adjust the CO2 to around 20-30 ppm. Then the only unknowns are the nutrient levels. (Joy! More test kits! )

If you do decide to pop for Nitrate and Phosphate test kits, be certain to get kits that read at low concentrations (low range test kits). If Read Sea sells in the UK, they make very good low range test kits for Nitrate and Phosphate. In the US, these kits sell for $8 to $12 each. Nitrate at 5 to 10 ppm and phosphate at .5 to 1 ppm are the targets your shooting at. So you'll obviously need test kits that read out noticeable color changes at these low levels. The Red Sea low range nitrate test reads from 0 to 30 ppm and the phosphate test reads from 0 to 2 ppm.

Red Sea products are made in Israel. They have a European office in France:

Red Sea Fish Pharm. Ltd.
Z.A. del la Saint-Denis
F27130 Verneuil s/Avre
France
Telephone 33-2-32377137
E-mail: [email protected]
Good Luck!

Tim

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post #8 of 19 (permalink) Old 12-05-2003, 09:53 AM Thread Starter
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My tap water tested at pH 7.5, kH 25 after standing for 24 hours. That makes 24ppm co2 (?). I've requested a water quality report from my supplier to see what they are putting in the water !
As for my deficiency - definately light I'm afraid. I've 2 25W T8s over 180Litres.
I reckon I could wedge a 3rd 25W bulb along the back of the hood, would this be ok, or would this cause problems due to the higher amount of light at the back of the tank ?
I can't get one in the front as the tank is bow fronted (Juwel Vision).
I could buy a T5 compact hood but WAAAY too expensive for me..

Edited to correct kH reading
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post #9 of 19 (permalink) Old 12-05-2003, 11:27 AM
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gH of 25 or kH of 25? There is a big difference and gH doesn't determine CO2 levels. And your problem is light. CO2 is not going to help you much if at all at those light levels. You are barely at one watt per gallon.
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post #10 of 19 (permalink) Old 12-05-2003, 01:08 PM Thread Starter
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Yep, kH not gH.
Would an extra 25W bulb help much ?
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post #11 of 19 (permalink) Old 12-05-2003, 02:33 PM
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I don't see how it could be physically possible for the water to retain that much CO2 after standing for 24 hours. I strongly suspect that either the pH or the KH test is giving faulty results. Check for an expiration date on both of the test kits. (Or as you seem to suspect - there could be something unusual in the water that "fools" one of the tests.) I bet that when you get your CO2 test, it will not show anything like those numbers.

While any additional light is better than no additional light, Rex is correct - you really would have a better time of it if you could get your lighting in the 125 to 150 watt range. For a great discussion about how to inexpensively light a planted tank, check this link: https://www.plantedtank.net/forum/viewtopic.php?t=194 . It is the thread titled "Cheap Lighting - ODNO" in the FAQ forum here.

Best of luck!

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post #12 of 19 (permalink) Old 12-08-2003, 08:21 AM Thread Starter
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Unfortunately, I can't overdrive the lights as they are in a sealed unit, an extra bulb is the only option for me unless I can find £80 for a new T5 PC overtank light unit :?
I got a new gH/kH test kit this weekend - a titration kit. The results of my tank water are gH 240mg/l kH 140mg/l.
With my pH of 7.2 I think I have 15ppm CO2.
These results seem a bit more realistic
I didn't buy a CO2 kit as all I can find is one that tells you 3 results - Not enough, just right, or too much CO2.
The guy in the store said he'd never been asked for anything more accurate :shock:
I'm going to try to sell something to raise the money for the light unit and a bigger CO2 tank..
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post #13 of 19 (permalink) Old 12-08-2003, 09:38 AM
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Quote:
Originally Posted by tombsc
Unfortunately, I can't overdrive the lights as they are in a sealed unit, an extra bulb is the only option for me unless I can find £80 for a new T5 PC overtank light unit :?
That's the pits. If you're handy with wiring and like to tinker, you might consider building your lights (including the hood they go in). Many of the guys here have done so and I'm sure they would be glad to offer advice. In the US, you could probably build the setup you need for the equivalent £15 - £20 or thereabouts. You might want to browse through the DIY and Lighting forums here for some ideas.

Quote:
Originally Posted by tombsc
I got a new gH/kH test kit this weekend - a titration kit. The results of my tank water are gH 240mg/l kH 140mg/l.
With my pH of 7.2 I think I have 15ppm CO2.
These results seem a bit more realistic
Yes indeed! Much more believable.

Quote:
Originally Posted by tombsc
I didn't buy a CO2 kit as all I can find is one that tells you 3 results - Not enough, just right, or too much CO2.
Now THAT'S useful. I've seen those over here too. Those usually contain pH indicator solution on the theory that if the pH is low, CO2 must be responsible. For people like you and me with hard water, those things are pretty much useless. I tried one before I learned what they really were. Mine never said I had enough CO2. Even when the Lamotte CO2 kit said the CO2 was 30 ppm!

Quote:
Originally Posted by tombsc
The guy in the store said he'd never been asked for anything more accurate :shock:
Same here. Most local pet shop owners give you a blank stare when you start asking for things planted tank keepers need. A lot of us end up having to mail order most of the things we need.

Quote:
Originally Posted by tombsc
I'm going to try to sell something to raise the money for the light unit and a bigger CO2 tank..
Like Rex suggested... I would recommend you do something about your lighting first (buy or build) and then try to improve your CO2 setup if you still think you need to. With lots of light, your plants will make lots of O2 - which means you can turn off your airstone completely - which means you won't use up CO2 nearly so fast from your system to keep the CO2 level where you want it. So maybe you won't need a bigger CO2 tank if you're not using the CO2 so rapidly.

I promise I won't go on for 5 paragraphs here... But the other thing that I had lots of trouble with when I first set up my pressurized CO2 was leaks.. lots of small leaks. When I found and fixed them all, my CO2 use went down dramatically.

Things to check:
The connection where the regulator screws on to the bottle (there should be a plastic or fiber washer in there - which should be replaced with a new one when you change/refill your bottle - a welding shop (or wherever you get your CO2 bottle refilled) is a good place to look for replacement washers);

the connection where the needle valve screws into the regulator (should be sealed with something like teflon tape);

the needle valve itself (my first one leaked around the valve stem);

every place the tubing connects to something else (needle valve, bubble counter, CO2 reactor) - use wire ties or clamps to tightly secure the tubing to the barb(s);

the bubble counter itself (mine had a leak in the top);

the tubing itself (must be CO2 "safe" tubing to prevent CO2 from leaking right through the walls of the tubing - my first tubing wasn't CO2 safe).

To test for leaks inexpensively, make some soapy water and get a small artist's brush and "paint" the area you want to test. Then look for tiny bubbles.

Good luck!

Tim

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post #14 of 19 (permalink) Old 12-09-2003, 08:38 AM Thread Starter
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I checked my CO2, its not leaking. The bottle is only 500g so a bigger one would be better.
Got the water quality report yesterday - Phosphates are at 2000ppBillion from my tap - I think this is 2 ppm (2000/ 1,000,000,000 = 2/ 1,000,000). Is this a high amount ?
Also they reckon kH should be 139ppm maximum so my test of 140ppm is pretty accurate. It also appears I am unlucky, just around the corner the kH is 15ppm (0.8 degrees).

I will get the new light unit when I sell my Ebay item - Will increasing the light so dramatically give me more algae initially until a new balance is found ? I don't want a high maintanance tank as I'm going to Mexico next year for 10 weeks and leaving my 'fish-resenting' girlfriend in charge !
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post #15 of 19 (permalink) Old 12-09-2003, 06:22 PM
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Got the water quality report yesterday - Phosphates are at 2000ppBillion from my tap - I think this is 2 ppm (2000/ 1,000,000,000 = 2/ 1,000,000). Is this a high amount ?
Yes. It is about 10 times the amount of phosphate that my tap water contains (0.2 ppm). Phosphate levels in a planted tank should be in the 0.5 ppm to 1 ppm range - in a 1 to 10 ratio with nitrate .5 ppm phosphate and 5 ppm nitrate, for example. I agree with your math, 2000 ppb ought to be 2 ppm. But boy that seems high right from the tap! This could account for some of your algae troubles if it is correct.

Quote:
Originally Posted by tombsc
I will get the new light unit when I sell my Ebay item - Will increasing the light so dramatically give me more algae initially until a new balance is found ? I don't want a high maintanance tank as I'm going to Mexico next year for 10 weeks and leaving my 'fish-resenting' girlfriend in charge !
Yes, most likely it will. With phosphate levels that high, the additional light plus the added CO2 could really send you round the bend. You are probably going to need to remove some of that phosphate if you go with high lighting and CO2 (Pre treat your water change water with SeaChem PhosGuard phosphate remover or something similar). That's something your girlfriend may not be willing to fiddle with while you're away. You might want to consider sticking with low light plants and your current setup until you return. Or, take her out to dinner often and buy her lots of presents before you leave!

Good luck!

Tim

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