Phospate stays at zero

Frans1992 · Feb 5, 2023

Hello,

I have a 80l (21 gallon) reef tank. My nitrate test a bit high arround 10 until 25. But my phosphate is going down every day to 0.00 (hanna checker). I dose every day the max ammount from the bottle po4+ (oceanart). The bottom of my thank is very fast dirty and there are some little spots of hair algae. Do I need to dose even more? My lfs said that the bottom is getting dirty fast because of to less po4 the nitrate will fall down.

Screwgunner · Feb 5, 2023

So no water changes for a whole month. Your goal is to keep all those peramiters to stay the same. You need fish and feed them before you get nitrates and phosphates. Frozen food will add more nitrates, pellet or flake food will add more phosphates. Weekly 10% water changes will help to keep peramiters more stable.

miller75 · Feb 5, 2023

Is the tank new? We had the exact same problem, if it is new keep dosing I think your rock and sand are absorbing it until it gets to a level and then it will start showing.

At least that's my understanding

Frans1992 · Feb 5, 2023

Screwgunner said:
So no water changes for a whole month. Your goal is to keep all those peramiters to stay the same. You need fish and feed them before you get nitrates and phosphates. Frozen food will add more nitrates, pellet or flake food will add more phosphates. Weekly 10% water changes will help to keep peramiters more stable.

Yeah i do that now, the high spike was because i put to much of reef balance in

Randy Holmes-Farley · Feb 5, 2023

I don't know anything about the suitability of the oceanart product, but in general, there's no limit to how much phosphate you can dose if you believe the readings are reliable.

Seansea · Feb 5, 2023

Feed your fish twice a day. With only a couple of small spots of hair algae i would say thats not whats consuming your phsospates. Generally if you feed fish heavy you will get some phosphates and your fish will thank you. Are you running a ATS?

X-37B · Feb 5, 2023

I have to dose po4 in my 80 to keep it above 0 and I practice heavy in/out so the tank gets plenty of food.
I can dose pellets for the fish and raise my po4 but its easy to over do unless you test frequently.

You should be able to dose po4 and test around 2hrs after to see po4 go up.

Some systems will use po4 faster than others so testing is key to keep levels stable.

I can look at my corals and tell if po4 is low just by the color as they fade out in my system if po4 bottoms out.

Frans1992 · Feb 5, 2023

Seansea said:
Feed your fish twice a day. With only a couple of small spots of hair algae i would say thats not whats consuming your phsospates. Generally if you feed fish heavy you will get some phosphates and your fish will thank you. Are you running a ATS?

No only a skimmer

AV corals · Feb 5, 2023

Never tried oceanart or even heard of that but I would turn off every nutrient export at night and back on in the morning. Also those nitrates are not high whatsoever. If you’re corals are happy keep those nitrate levels. Don’t chase textbook numbers but I would recommend dosing NeoPhos from brightwell. Highly effective.

Frans1992 · Feb 5, 2023

AV corals said:
Never tried oceanart or even heard of that but I would turn off every nutrient export at night and back on in the morning. Also those nitrates are not high whatsoever. If you’re corals are happy keep those nitrate levels. Don’t chase textbook numbers but I would recommend dosing NeoPhos from brightwell. Highly effective.

Oke i will give it a try

mtraylor · Feb 5, 2023

Is this a new tank started with dry rock? If so it will take some time to get some phosphates in the system and sustainable. I dosed my frag tank for months. Never really got a descent reading that lasted over 12 hours, but once they showed up to about .03ppm then I stopped dosing

Frans1992 · Feb 5, 2023

mtraylor said:
Is this a new tank started with dry rock? If so it will take some time to get some phosphates in the system and sustainable. I dosed my frag tank for months. Never really got a descent reading that lasted over 12 hours, but once they showed up to about .03ppm then I stopped dosing

It's about a year old now

Frans1992 · Feb 20, 2023

After a long time of adding po4+ from aquaforest every day i got a reading from 0.02. My nitrate went completely down from 20 to 2.5. the only problem i have now is that my zoanthus are closed up very weird. Can this come from the fast change in nitrates and phosphates. Also one fish died, but I pulled it out very fast. Can this also be the reason. I don't read any amonia so i don't think so.

Randy Holmes-Farley · Feb 20, 2023

I'd feed more or keep dosing N and P.

RGoltz · Feb 20, 2023

The problem with dosing phosphate is that it may be binding to other surfaces in the tank. So, you may dose and dose it only be feeding algae (that consumes phosphate very quickly) or binding the phosphate (which will be a hassle later).

Assuming that this is a young system - and particularly if you are not keeping delicate corals - I recommend to not chase after nutrients like this.

Clear the algae by hand and watch what you feed your fish.

Harold999 · Feb 20, 2023

I have the same mystery happening with a 10g tank. I dose 2 drops po4 a couple of times per day for more than a week now and po4 still won't show up.
There are no rocks in the tank, just some corals straight on a thin sandbed.
I'm flabbergasted.
If i dose a drop of the same po4 in a bucket of water po4 goes through the roof, so it's definetely not my testing methods (Salifert + Hanna).
Looks like something mysterious in the 10g tank is turning po4 immediately into something different but i guess that is not possible?

Randy Holmes-Farley · Feb 21, 2023

Harold999 said:
I have the same mystery happening with a 10g tank. I dose 2 drops po4 a couple of times per day for more than a week now and po4 still won't show up.
There are no rocks in the tank, just some corals straight on a thin sandbed.
I'm flabbergasted.
If i dose a drop of the same po4 in a bucket of water po4 goes through the roof, so it's definetely not my testing methods (Salifert + Hanna).
Looks like something mysterious in the 10g tank is turning po4 immediately into something different but i guess that is not possible?

It normal, not a mystery. It is binding to rock and sand, and partly being taken up by organisms. Dose more.