Can phosphorus lead to increased metal staining

[smallpooldad]

As phosphorus in water absorbs iron would more phosphorus in the water create a greater potential for staining?

Please see site below.

http://www.euroharp.org/toolbox/p1.php

Looking forward to your replies.

[waterbear]

The type of phosphorous that causes probems in pool water (maybe!) is orthophosphates...algae food. The fact that some phosphorous compounds react with metals is what makes sequestering agents work! They are mostly phosphonic acid derivatives such a HEDP.

[smallpooldad]

Thank you for your reply.

I am not sure I understand the reply.

So far from other posts I am aware that phosphates are an additional food source for algae and that they normally only cause a problem if nitrates are present. Also that the potential for algae growth is there if insufficient chlorine is present. Phosphates therefore can further increase the likelihood of algae, as they are also a food source for them. So reducing phosphates can help, but I have no algae and no nitrates. I believe this is the case in the majority of pools except those close to sources of wind born nitrate fertilizers. So reducing them for this reason is typically a waste of money in my case.

The question is does it increase the potential for iron staining, if phosphates increase the oxidation of iron and other metals (maybe it does not)? Can this further increase the potential for staining, in that other forms of iron now becomes rust (ferric oxide).

Phosphorous I understand from your reply sequesters iron, which can drop out of solution, by doing so it appears that it might also create a problem via the afore-mentioned further oxidation, would it be better to use a non-phosphorous sequestering agent such as Metal free which is non-phosphorous as you mentioned in a previous post? Might you know what the active ingredients are and the percentages? From your previous post you stated that Metal free is not as effective so could, or should, one increase the dosage or, as is the case with polymers, this potentially be a bad idea?

I realize that this is a little pedantic and could be erroneous but it bears consideration?

Please excuse me if I did not make that clear.

On the lighter side I am considering purchasing a small jet engine to create giant bubbles in my pool to blow all the the iron out. Believe it or not this would actually work. But then again I might lose all the water or reduce the alkalinity to zero

Looking forward to all your replies.

[waterbear]

Phosphorous comes in different forms. Orthophosphates are algae food. As far as I know they do not sequester metals. Metal sequesterants can form orthophosphates when they break down.
If you pool has no nitrates, high orthophosphates, and algae blooms that you cannot control then a phosphate remover might be benificial by removing the algae food souce. If nitrates/nitrites are present then it won't since they are algae food also.

Metal Free uses EDTA as the chelating agent. IMHO, it is not as effective as phosphonic acid based seqeusterants. I have used both kinds and I don't feel the EDTA works as well (I tend to keep going back to Proteam Metal Magic...HEDP...a phosphonic acid derivative)
Sequestering agents have a 'chelation index' for different metals. This means that it will sequester one metal more than another...for example, Jack's Magic blue stuff has a high chelation index for copper so it will sequester copper before other metals...so called calcium hardness reducers have a high chelation index for calcium (yes, it's a metal) so they sequester that first. If I am not mistaken the chelation index for different metals with EDTA becomes very pH dependant.....That is why it is used at the titrant in the calcium harndess test at a pH of 12 and used in the total hardness test at a pH of 10 where it chelates both calcium and magnesium.
I have orthophosphate readings well above 1000ppm (I estimate beteen 2000-3000ppm), no nitrate/nitrite and I have NEVER had an algae bloom (nor any CC for that matter!) I do have a SWG, run my cya at 70 ppm and keep my FC between 3-5 ppm.

I think you are looking for problems when there aren't any. Do you have repeated uncontollable algae blooms? If not don't loose any sleep over it.

[smallpooldad]

Waterbear,

Thank you for the detailed explanation. As far as Phosphorous Remover I do not think I will ever use it again see my recent post on how it lowers CYA.

http://www.poolforum.com/pf2/showthread.php?t=4863

As far as a sequestering agent goes I will stick to the ones that use Phosphorous, as you stated they work better.

One question for you is, do you know what the major chemical ingredient(s) is/are for Jack's Magic Copper Remover?

Thank you for all the time you spent on this, it was very beneficial.

Aloha

[waterbear]

Waterbear,

Thank you for the detailed explanation. As far as Phosphorous Remover I do not think I will ever use it again see my recent post on how it lowers CYA.

http://www.poolforum.com/pf2/showthread.php?t=4863

As far as a sequestering agent goes I will stick to the ones that use Phosphorous, as you stated they work better.

One question for you is, do you know what the major chemical ingredient(s) is/are for Jack's Magic Copper Remover?

Thank you for all the time you spent on this, it was very beneficial.

Aloha

I According to the MDSD Jack's Magic Blue stuff is HEDP (1-Hydroxyelthylidene- 1, 1-
diphosphonic Acid)