Question:

Can you tell me how much water outlet(liter/hour) from deltec FR 509 with rowaphos 500 ml for my 900 liter tank with many sps?

Now i use eheim 1048 for feeding Deltec FR 509 but i do adjust value for low water pass rowa. I can see when i adjust very very low water pass PO4 out of reactor is 0.02-0.03 but in my tank PO4 about 0.09-0.10. If i adjust very high water pass PO4 out of reactor is 0.11 and in my tank PO4 is 0.11.I am very confused by this problem.

2.My deltec FR 509 has 2 sponges fist is fine sponge and second is rough sponge. Do i use fine sponge on the top of reactor or buttom of reactor

Answer:

The FR509 reactor should have a flow of about 500 litres per hour.

Rowaphos will not remove all of the phosphate from the water on a single pass if it is passed through at the normal speed but will gradually remove more on each pass.

If you slow the water level down then you will be able to see the reduction in the amount of phosphate and if you slow it right down then you can get zero coming out of the reactor.

I find it hard to believe that you can distinguish between 0.09 and 0.11 as the readings are almost identical and even dirty phials will make this difference.

You may have phosphate in your rocks and sand which is still releasing.

If the phosphate in the substrate is in balance at 0.10 then as you take the phosphate out of the water it will release back from the substrate until it is all removed.

You obviously still have life left in the Rowaphos as you can slow it down and get a lower reading. Leave this on until you can no longer reduce the reading no matter how slow you run the water flow and then change it. Once you have drawn the locked up phosphate from everything in the tank then it should be simple to keep the readings at zero.

The fine sponge should be at the top however it is possible to run the reactor without any sponge at the bottom. This prevents blocking of the sponge which is not so easy to clean as the top one.