[jbl429]

Hi! I have a fairly heavily planted tank (Red Sea Reefer 350), but can not get my nitrates down to a reasonable level. The tank is consistently at the highest level on my API test kit and my tap water is in the 20ppm range. I am using sand as my substrate, but about a month ago introduced two BCB baskets into the sump and have been putting laterite under the sand bed through the ice cube method for the past few weeks as well and have not seen the nitrates drop at all. What can I do to get these down to a normal level?

I'm thinking I need to switch to RODI? Do I need to remineralize at first, or should I be putting in pure RODI until the levels lower? Is there any other solution?

 

[Phil Edwards]

If your tap water has 20 mg/L NO3, go with it! Are you adding additional NO3? What else are you supplementing and what are their concentrations? The usual causes of NO3 not dropping are heavy stocking and feeding, slow plant growth (lots of slow growers) and/or insufficient other nutrients; typically PO4 and K causing normally fast growers to not grow at their full potential.

Would you please share some pictures of the tank, your current nutrient concentrations, and dosing schedule?

 

[jbl429]

Thanks Phil!

I'm dosing GLA PPS-PRO method (daily), however, this has been an issue in the tank since before I was using these ferts, and it hasn't had an effect on the Nitrates, even when I skipped the KNO3 part for a month.

My last test showed

Ammonia: 0.0
Nitrites: 0.0
Nitrates: off the chart... 160?
pH: 7.4
kH: 4
gH: 4
PO4: 5.0

It's stocked with 7 boseman rainbowfish (all juvies, with 3 of them being 1.5 inches), and about 15 other fish between Tiger Barbs, Rummynose Tetras and Siamese Algae eaters. A handful of Mystery snails as well.

Here's the most recent pic I have of the tank: New photo by Jeff Levitt

 

[Phil Edwards]

Are you adding a source of carbon? Most of your plants look like they're disintegrating or are spindly. If your NO3 and PO4 are actually what your tests are saying they are, the most likely culprit is C. If you're not able to put a pressurized CO2 system on the tank and/or aren't interested in a liquid carbon source like Excel, it wouldn't hurt to add an air bubble wand to increase gas exchange. It's not ideal, but it's better than nothing. Something else to consider is to let the lilies grow up to the surface to reduce some of the light. Adding some floating plants will help with that as well as take up nitrates and phosphates.

One last thing- since your tap has 20 mg/L NO3, try doing a number of large water changes to bring it down to that level; it's nearly perfect. Once you get that you'll just need to keep your PO4 and K in a decent range.

I hope this helps,
Phil

 

[jbl429]

Thanks for the quick responses, Phil. I should have mentioned, I do have pressurized CO2 going through a Cerges reactor on the return line from the sump. I think the spindly plants are because I've had to keep the lighting lower intensity as high lights with high nitrates has been contributing to algae growth. Algae has been better lately, but I don't think the plants are happy with the amount of light.

I don't stop the lillies from hitting the surface, but they typically send one leaf to the surface at a time, and don't cover the surface much. I can't do floating plants in the display with this setup because they get pulled into the overflow, but I do have a good amount of them in the sump.

I've also done some large water changes in the past. I did two 50% water changes about a week apart and the Nitrates were back to high levels quickly.

 

[SteveM]

160ppm is crazy high. I would be doing large volume water changes daily to bring that down as a priority. Something like a third of the water volume twice a day or half daily. Might be worth trying another brand like salifert test kit just be sure you're getting accurate results with API.

Next would be to figure out the source of your excess nitrates. Weekly gravel vac and regular filter cleanings are key, but I would bet it's from the GLA fertilizer. You might need to customize the mix to dose less nitrate or none at all if your tap water provides enough to maintain around the 20-30ppm range. Still of course need to keep up with dosing the other macros and micros.

RO is an option and gives you complete control of your water parameters but is more money and work. I'd try working with tap water before going the RO route.

 

[jbl429]

Thanks Steve, I'll try a different test kit as well, could be that. I was having the issue long before switching to the GLA fertz, so I don't think it's that, but it could be a contributing factor. I'll do a bunch of water changes too.

I don't mind setting up a RO system. I might do that anyway just to have more control. To start would I remineralize completely, or go with pure RODI water to try and remove as much nutrients from the water as possible?

 

[MoreliaViridis]

Thanks Steve, I'll try a different test kit as well, could be that. I was having the issue long before switching to the GLA fertz, so I don't think it's that, but it could be a contributing factor. I'll do a bunch of water changes too.

I don't mind setting up a RO system. I might do that anyway just to have more control. To start would I remineralize completely, or go with pure RODI water to try and remove as much nutrients from the water as possible?

Plants need GH chemicals, ie Ca and Mg. For KH usually not so much.
Most tap already contains plenty of GH so usually ferts have no/little Ca and Mg content and people can get away without dosing additionally.
But when you switch to 100% RO/DI...then all of a sudden you only have tiny amount of Ca/Mg.
They are secondary macros so..plants need those lot more then traces. So yes remineralize.




I would first look at the source of NO3
If tap is really 20 ppm and you are not adding that much ferts, then it has to be from substrate or feedings. (Or test is off)
Do 70%+ WC and reduce feeding by 1/3. No they are not going to starve to death.
Wait out for a week and see. If NO3 is very high again then its most likely stuffs you added into the substrate.

 

[Kubla]

It's a bit of work but if you calibrate your test kit you'll be able to tell how accurate it is and make adjustments.Calibrating Test Kits - for non-Chemists

 

[SteveM]

Good advice above. Plants and possibly fish won't do well in straight RO water.

When I used RO from a kitchen faucet at my last house, I remineralized with Seachem Equilibrium. It needed a couple days to fully dissolve in the RO water so I felt like I was constantly prepping water in buckets all week for weekend water changes. There was probably a better way to do it...

 

[Greggz]

It's a bit of work but if you calibrate your test kit you'll be able to tell how accurate it is and make adjustments.Calibrating Test Kits - for non-Chemists

+1.

Before you make decisions based on readings, make sure those readings are correct.

I am betting they aren't.

Here's more directions on making test samples.

 

[Greggz]

Good advice above. Plants and possibly fish won't do well in straight RO water.

Completely false.

Plants and fish do very well in straight RO water.

Especially plants. Most all actually do better in zero dKH.

Here is a good article to learn more. My tank is pictured there when it had 1.00 dKH but it's now been zero for quite some time.

Low dKH 2hr Aquarist

 

[MoreliaViridis]

Completely false.

Plants and fish do very well in straight RO water.

Especially plants. Most all actually do better in zero dKH.

Here is a good article to learn more. My tank is pictured there when it had 1.00 dKH but it's now been zero for quite some time.

Low dKH 2hr Aquarist

He is probably referring to GH as he was referring to my post above and I was talking about GH mainly.

Plants and almost all SA/SAE fish indeed do well on 0dKH.

 

[SteveM]

Completely false.

Plants and fish do very well in straight RO water.

Especially plants. Most all actually do better in zero dKH.

Here is a good article to learn more. My tank is pictured there when it had 1.00 dKH but it's now been zero for quite some time.

Low dKH 2hr Aquarist

Simply meant that straight RO water, without remineralization, is not a recipe for success with plants. Sorry if that wasn't clear from my post.

I used only RO water at my previous residence for the last two years, but remineralized up to about 7dgh.

 

[Phil Edwards]

Thanks for the quick responses, Phil. I should have mentioned, I do have pressurized CO2 going through a Cerges reactor on the return line from the sump. I think the spindly plants are because I've had to keep the lighting lower intensity as high lights with high nitrates has been contributing to algae growth. Algae has been better lately, but I don't think the plants are happy with the amount of light.

I don't stop the lillies from hitting the surface, but they typically send one leaf to the surface at a time, and don't cover the surface much. I can't do floating plants in the display with this setup because they get pulled into the overflow, but I do have a good amount of them in the sump.

I've also done some large water changes in the past. I did two 50% water changes about a week apart and the Nitrates were back to high levels quickly.

You did exactly the right thing by lowering light intensity. Are you able to increase intensity to somewhere between what you have now and what you had? In the past I've used lights without dimmers and could only control illumination by removing bulbs (T5) or shutting off one of the fixtures I was using (LED strips) so I understand if that's not possible for you.

If you want to try floating plants with an overflow there's a fairly easy trick; grab some black plastic mesh normally used for thread arts, put some suction cups on either side, and stick it to either side of the tank about an inch from your overflow. Think of it as a gutter guard for the tank. I normally use this to make planted walls, but it works well to keep floating plants and dead leaves from blocking the over flow. The nifty thing about this is you can make it as short or as long as you want so it can become a fully planted wall covering the overflow so you don't have to look at a big plastic thing in the tank. As long as you leave a couple of inches of space between the mesh and the substrate you'll still get good flow into the overflow.


I forgot to ask; what are you using for bio media?

 

[Greggz]

He is probably referring to GH as he was referring to my post above and I was talking about GH mainly.

Plants and almost all SA/SAE fish indeed do well on 0dKH.

Yep sorry I see that now.

He wrote dKH but was referring to dGH.

 

[jbl429]

I forgot to ask; what are you using for bio media?

I'm using ceramic rings in one filter bag and about 15 pounds of additional rock in the sump.

I'm going to do a bunch of large water changes this weekend and will see how much it drops the Nitrates and how long it takes to come back. I'll also test nitrates with another kit. I have a feeling it's the culprit for my algae issues though, as the rest of my water parameters are fine and stable.

 

[Phil Edwards]

I'm using ceramic rings in one filter bag and about 15 pounds of additional rock in the sump.

I'm going to do a bunch of large water changes this weekend and will see how much it drops the Nitrates and how long it takes to come back. I'll also test nitrates with another kit. I have a feeling it's the culprit for my algae issues though, as the rest of my water parameters are fine and stable.

How easy would it be for you to give the biomedia a good flush to reduce particulates from it to see how much that helps?

 

[jbl429]

How easy would it be for you to give the biomedia a good flush to reduce particulates from it to see how much that helps?

Would be pretty easy. I'll do it with my water changes this weekend!

 

[Phil Edwards]

Would be pretty easy. I'll do it with my water changes this weekend!

Cool. That's something I recommend doing once a month or so just to make sure you're not blocking biologically useful surface area and don't have so much gunk in there that it becomes a significant source of nutrient addition. Just make sure you don't use raw tap water.