my thoughts on phosphates

[Sk8r]

Let me add about overdoing it: my blennies did NOT appreciate the scarcity of phosphate, ergo algaes that they eat. I ended up tossing quite a few algae tablets in to tide them over and INCREASE the phosphate. My corals (lps) couldn't care less.

 

[grouper therapy]

The amount of phosphate that GFO can bind is a function of the final phosphate concentration you want to get to. You bind a lot when the phosphate is 3 ppm, and bind very little when the phosphate concentration is 0.01 ppm.

But empirically, many reefers know that they can bring the phosphate concentration quite low with $100 worth of GFO, and in fact, need to be cognizant of overdoing it, which happens reasonably frequently, while $100 worth water changes just doesn't do the trick for most people.

So the higher the concentration of phosphates the more efficient it becomes?
Do you think it is possible to maintain a low phosphate level with regularly scheduled water changes alone once the gfo has lowered them to that level? Of course with minimum introduction of more phosphates and proper maintenance.

 

[Randy Holmes-Farley]

So the higher the concentration of phosphates the more efficient it becomes?

Yes, that is true of almost anything that binds phosphate.

Do you think it is possible to maintain a low phosphate level with regularly scheduled water changes alone once the gfo has lowered them to that level? Of course with minimum introduction of more phosphates and proper maintenance.

Not normal water changes, since there is enough phosphate in a single day of feeding to bump phosphate from none up to 0.1 to 0.4 ppm.

Every reef tank needs substantial ongoing export of phosphate.

 

[grouper therapy]

Yes, that is true of almost anything that binds phosphate.




Not normal water changes, since there is enough phosphate in a single day of feeding to bump phosphate from none up to 0.1 to 0.4 ppm.

Every reef tank needs substantial ongoing export of phosphate.

I'm setting up a 116 gallon cube and was considering setting up a continuous water change system on the tank. Starting out with ULNS and very low bio load. do think it possible to maintain that ULNS with a
a continuous water change? I'm was going to try 5gallons a day.

 

[Randy Holmes-Farley]

I do not think it likely that you'll keep phosphate adequately low to keep it ULNS with water change only, no.

It is easy enough to try and see what happens with almost any plan, however. I would just expect it likely you'll have to add additional export.

 

[tmz]

I like frequent and small water changes for a variety of reasons. 130% per month is significantly more than the typical 20 to 40% per month and will have some effect on PO4 and other nutrients but I don't think it will keep PO4 low enough for sps in a tank that is fed . It might but overtime inorganic phosphate the will likely build up with o a 4% daily export via water change, depending on the idiosyncrasies of the particular aquarium.

If cost comparisons are driving the decision , note, gfo can be regenerated lowering the cost considerably with a little extra work.
There are other methods too: organic carbon dosing, macro algae, lanthanum chloride , and so so on which may work well enough singularly or in combination in a particular application.

 

[reefgeezer]

I think that most test kits are useless at low levels of phosphate. IMO, it is smart to assume that there is always phosphate that needs to be removed. I use small water changes, Cheato, GFO, and carbon dosing.