Nutrient Reduction

[ggNoRe]

I have a 200G system that has been up and running for about 20 months. Over that time my nutrients have continued to climb. I just got ICP results showing 50 nitrates and .89 phosphates. I test weekly and for 2 months I've been testing around 30 nitrates and +.9 phosphates which is the maximum on the hanna checker consistently. I have always done weekly 10% water changes very consistently, use filter pads, filter socks (reef diaper) under the filter pad, an oversized Aquamaxx skimmer rated for 350G, chaeto (which has stuck around for about a year but does not grow), for about a month now I started using Rowaphos and have increased the amount to enough rated for 125 gallons, and I have reduced feeding quite a bit for about a month as well. All of this and my nutrients still aren't going down. My fish and corals seem to be doing ok however. I'm starting to consider carbon dosing. Any thoughts on this? Any suggestions? If you suggest I carbon dose, which source should I use and at what recommended dose?

Thanks

 

[Reef.]

What test do you use for po4? By the look of your tank, I would be doubting the 0.9 result.

 

[ggNoRe]

What test do you use for po4? By the look of your tank, I would be doubting the 0.9 result.

Hanna ULR. I doubted my results purchased a second one and got the exact same results. Also, ICP came in at .89

 

[Reef.]

Phosphorus or phosphate?

your Hanna gave the same reading as icp?

Purchased a 2nd what? Hanna or icp test? I would trust the Hanna over the icp for po4. What was the Hanna reading?

 

[slythy]

Test fresh mixed seawater just to make sure we arent taking crazy pills.

 

[ggNoRe]

Phosphate. 2 hanna checkers. Icp .89 hannas .9+ which is the max they can test

 

[Reef.]

If you po4 is really that high your rowaphos will be getting exhausted within hours, you need to be changing it very often, and be using a reactor, Rowa in a media bag is very inefficient, change it daily or twice a day until you see a drop on your Hanna checker, then you can go to changing it when you see an increase in your po4 on the checker, which will again be within a day or two, as you remove the po4 from your water, the rock and sand will release the po4 they are holding onto.

With your tank being so big, don’t be surprised at the amount of rowaphos you will need, and I would up your amount, as said if your lvl really is .9 then I would be using the correct amount for your tank, not just over half the amount as you have been being.

Take your time as you want a slow drop in po4.

I would be looking at your nutrient removal methods as they are clearly not working. If you test so often, the question has to be why did you not correct the po4 lvl sooner?

 

[ReefGeezer]

Carbon dosing might be a good way to address the nitrates. I prefer regular old vinegar. It is safe and easy to dose and doesn't seem to encourage Cyano as much as other carbon sources.

If your Cheato isn't growing with the nutrient levels you report, light, flow, potassium, or iron may be low. Dosing iron may also help reduce phosphates.

Your phosphates won't be effectively lowered by carbon dosing and things like GFO will exhaust quickly and be expensive in your big ole tank. Take a look at Lanthanum Chloride dosing to get it under control. Lanthanum Chloride has some risks so read up and make sure you dose it correctly.

 

[ggNoRe]

Carbon dosing might be a good way to address the nitrates. I prefer regular old vinegar. It is safe and easy to dose and doesn't seem to encourage Cyano as much as other carbon sources.

If your Cheato isn't growing with the nutrient levels you report, light, flow, potassium, or iron may be low. Dosing iron may also help reduce phosphates.

Your phosphates won't be effectively lowered by carbon dosing and things like GFO will exhaust quickly and be expensive in your big ole tank. Take a look at Lanthanum Chloride dosing to get it under control. Lanthanum Chloride has some risks so read up and make sure you dose it correctly.

Finally a response to the direct question!

Thank you

I did a deep dive on another thread that goes into carbon dosing in great detail. Going to take it slow and see how things go with more GFO for a little longer and if it doesn't get better will slowly introduce vodka or white vinegar. Mainly just because I'm lazy and they are easy to source.

 

[ReefGeezer]

Finally a response to the direct question!

Thank you

I did a deep dive on another thread that goes into carbon dosing in great detail. Going to take it slow and see how things go with more GFO for a little longer and if it doesn't get better will slowly introduce vodka or white vinegar. Mainly just because I'm lazy and they are easy to source.

Vinegar and/or vodka are fine carbon sources. You really don't need any other source... the rest is just marketing.