High Phosphate hurting Zoa's, can I beat this?

[Azteky]

Our tank used to thrive, our Zoa's exploded and everything was going great. I Vodka dosed 3ml a day and only added tap water for evaporation, no water changes at all, I did this for 4 years. However over the last 8 months or so we added a lot more fish and much more corals to the tank (72 gallon bowfront, no sump) and it is now going down hill..

I have since bought an RO/DI unit, and have been doing water changes every few weeks, but our Zoa's are just not the same. I do have high phosphates (Around .4 - .5) but all other parameters are in line. Salinity 1.026, temp 79-80, Alk 8.5-9, etc etc.

We have a deep sandbed with loads of liverock, the tank is clustered with them, so I am wondering if that is my issue, now they might be soaked with phosphate and leeching into the water. I have bought some Phosphate RX and can easily take it down to 0, but after a few days it starts jumping back up to around .5 again after a week or two.

We don't have pests, so I'm thinking of idea's.. So far I'm at the mind set to keep using the phosphate RX until it starts taking it out of the rock/sand, to remove either now would be too much, and it would be easier to just restart the whole tank. I have tried using a GFO and that doesn't help either. I can slowly add more vodka (Carbon dosing) to see if that helps!? Anyone have some other idea's, would the phosphate rx eventually keep it down, and that's only if the phosphates are the issue..

The attached picture is from around a year ago, when things just started to get worse..

 

[sde1500]

Carbon dosing really works better for Nitrates. It could help with phosphates if the two are pretty well balanced out but in this case doesn't seem to be the case. Seems kind of like a case of older tank without water changes let the rock absorb tons of phosphate which it is now releasing.

I've been running GFO and recently switched to an algae reactor. But a lot of people seem to have success using lathium chloride. Though that may be hard without a sump.

 

[Azteky]

Yeah, I really do wish I knew back then that I needed a sump and it would have made things so much easier now!

Maybe I'll try and keep up with the phosphate RX and hope it eventually sucks it out of the rocks and sandbed..

 

[sde1500]

Do you have a stand with space under it? You could probably get away with installing one now. Use a HOB overflow, I've had one going for 10 months now, zero issues using it. Just have clean the U-tube out every few months due to some algae growing in it. Then could run a skimmer and other stuff underneath. And could drip the lathium chloride into the filter sock.

 

[Azteky]

I thought about that, as a sump would make things so much easier, I'm just worried as I have heard of so many horror stories with HOB overflows, either leaking or very noisy : /

 

[organism]

I used to use an HOB to a sump a long time ago and almost got evicted when it failed. Some people don't have issues, but if it fails on you then you are beyond screwed. Not worth the risk imo.

Phosphate RX doesn't necessarily remove phosphates and isn't going to work as a long-term solution. You'll need to run some kind of phosban media to remove phosphates from the tank if you want to go that route.

It's pretty likely you have old tank syndrome where your rocks and sand are full of nutrients, one way to treat it is to up your vodka dosing to keep up with the new fish. Do you have a good skimmer on the tank?

 

[Azteky]

Yup, Actually upgraded from a reef octopus BH-1000 to the BH-2000. I'm slowly up'ing the vodka, was at 3ml a day, will try and get to 4-5ml and see what that does over the next month or two.

 

[Scottedontknow]

honestly id pick up some BRS-GFO (in a media bag) and run it in an empty HOB filter if you have one laying around. it will help out until you can figure out a long term solution.