Zero Nitrates but high levels of PO4.What should I do to lower the PO4?

Oliver D

New Member
My tank has 0 nitrates but i have a high PO4 reading 2.0 on an API test kit .My nitrates are kept down with home made VVS and I am trying to lower the PO4 level with Rowa Phos but to no success. The Rowa Phos has been in for 14 days in a reactor.How long does it normally take to come down?
 

mr_tap_water

Well-Known Member
Hi there
The Rowa phos should start to work straight away in the reactor have you tested what's coming out and compare it to what's in your system also The Rowa should be just shimmering in your reactor to get the best from it, how long you leave it in there for depends on how quick it gets exhausted and needs to be changed well before reaches your tank levels, also I believe you need a little bit of No3 as these both feed off each other.


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SPR

Well-Known Member
I started using Rowaphos and I agree it works immediately but if you have a lot of phosphate you may need to change is quickly to start with as it becomes spent. Also maybe try using a bit more in the reactor so you don't need to change it as often

When I started using it my phosphates were way lower than yours at 0.16 and I had to change it after just 3-4 days to start with. I had been in touch with DD about a combination of things and they said just use extra to avoid changing as often in my size tank (i used double amount) until things are under control as you can't overdose on it.

You just need to test regularly as above the reactor out water and tank water and that will tell you when to change it and eventually once all phosphate has leached out of the rocks etc it should come down to

Having said all of this, also bear in mind that depending on what corals you have etc., it may be better to reduce phosphate slowly in case the corals have become accustomed to those high levels rather than a sudden reduction as they can be very sensitive.

My tank runs now at around 0-0.04ppm on both Red Sea Pro and Hanna test kits and I'm using around 500g Rhowaphos in a Deltec FR509 reactor for a rough actual water volume of 575litrs (Red Sea Max S650) and at the moment change the Rowaphos about every 4 weeks

Due to test kit inaccuracies and also feeding, your unlikely to have 0 phosphate even though a test kit says that, and also you don't necessarily want 0 Nitrate or phosphate as the water will be too clean and sterile.

So basically sounds like you need to change it, and then change more often, and it will work as it's very effective.
 
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DaveK

Well-Known Member
The first thing I would do here would be to get the water tested using a different brand of test kit. You want to verify that your test results are correct. If they are correct, then I would test your newly mixed batch of SW that you use for doing water changes. This might be a source of the problem.

Products like Rowa Phos will absorb phosphates, but once they absorb all they can, that's it. They will not absorb more, and the media needs to be replaced.

If your going to replace the media, consider using generic GFO. It's much less expensive than Rowa Phos and it's the same thing.
 
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