What is your phosphate management routine?

[fishytime]

I run Rowaphos(gfo) in a reactor
Cheato in the fuge
never have tested for phosphate

Phosphate test kits are a waste of money IMO.

[untamed]

My experience is almost identical to yours, Tony....right down to using the colorimetre.

To Marie's point... If you measured for phosphate, I bet you would be surprised. I started testing phosphate and trying to reduce phosphate because I grow a lot of algae and cyano and I'm always told "to get rid of cyano, you have to reduce nitrate and phosphate".

So here's the rub: I've never been able to measure any significant nitrate or phosphate in my system using the best measuring equipment that can be reasonably purchased. So I'm told "that's because all the algae and cyano are using it up before you can measure it".

I run RowaPhos in a TLF and change it out about monthly. I have never been able to determine if that is an adequate schedule or not.

I've been VSV (vodka, sugar, vinegar) dosing for almost two months now and in spite of increasing dosage nothing significant has happened. (I still measure almost zero nitrate and phosphate). Well...my chaeto has basically died so I guess something has happened....but I still have a lot of cyano issues.

[marie]

Originally Posted by untamed

....

So I'm told "that's because all the algae and cyano are using it up before you can measure it".

...

If that's the case then wouldn't the algae and cyano also be removing it before it can affect coral growth and therefore be a non issue?

[marie]

From my understanding, all living organisms uses phosphates to some degree and it follows any food you add to the system will have phosphates bound up in it (whether it's listed on the label or not).
The more animals and plants you have living and growing in your system, the more phosphates get taken out of the water column. Problems arise when there is too much phosphate getting bound up in the coral skeleton that's when it starts to affect tissue growth

....some phosphate good, too much very, very bad

[Lance]

My 90g has been running for 2 years and has a pretty large bio-load. I have never had noticeable PO4 or NO3 readings on either Salifert or Elos kits. SPS grows quite well in this tank and very seldom do I have issue with algae growth.
In the 225g tank however, SPS doesn't do crap. A few pieces do ok and others not so good. I am always having algae issues as well. P04 readings in this tank are undetectable and N03 are about 10 to 15.
Both tanks get 10% water changes bi-weekly, both have refugiums with DSB and large amounts of macro-algae. I have tried Tailored Aquatics Nitrate and Phosphate Destroyer; vodka dosing; and larger water changes on the 225g: with no positive results. SPS continue to struggle and algae growth has not been reduced.
The only difference I can see between the 2 tanks is the rock I used when setting up. The 90g was all live rock, while in the 225g I used a lot of BRS Eco-Rock. Perhaps there is a lot of phosphates bound up in this rock and continues to leach out.