Reduction of CH

[iwannapool]

If I were to reduce my CH, currently at ~250 ppm, how would I go about doing this, add TSP? If I were to reduce it, say to 150 ppm, would I be able to tell the difference in feel, i.e. would it feel softer?

Not sure if it's worth messing around with since my water is very clear and all levels are good and stable.

I have an IG vinyl w/SWG.

[KurtV]

Your CH is fine. You're at the low end of the recommended range of 200-400 ppm and since you have a vinyl pool, calcium doesn't matter very much (if at all) anyhow.

If you ever do need to reduce it, the only way is to drain some pool water and replace with lower calcium fill water. (I think there are also companies in places like AZ, where the water is extremely hard, that can remove calcium through some process.)

[iwannapool]

I thought I read somewhere you could lower CH by slowly adding trisodium phosphate. I believe this is the common cleaning product, TSP.

[fcfrey]

My old brain has lost a lot of what I learned in chemistry class in the 60s so I did a search on Trisodium Phosphate. Here is an extract from the Wikipedia listing:

"Similar chemicals were once common in laundry and dishwashing detergents, but the phosphate, being a fertilizer, would cause algal blooms in the bodies of water that the drains led to. In the early 1970s the use of phosphate-containing products was limited. Now products sold as TSP Substitute, containing 80–90% sodium carbonate, are promoted as a direct substitute."

Notice what it says about ALGAE---- Richard may want to weigh in, but I would not intentionally put phosphates in my pool.

[chem geek]

If you maintain proper chlorine levels, then phosphates will not cause an algae bloom. Basically, you can keep algae from growing in any number of ways:

1) Keep out all light. Algae needs at least some sun to grow (though not too much or the UV from sunlight ends up doing too much damage). Unless you are indoors and swim in the dark , this is not an option.

2) Take away at least one critical nutrient. This includes carbon from carbonates (can't take that away -- need it for pH buffer and calcium carbonate saturation), nitrogen from nitrates (hard to eliminate since it's in many bather wastes), phosphorous from phosphates. So really the only one you can realistically eliminate is phosphates (with a phosphate remover -- usually expensive), but it can always get blown in from farm (or your garden) fertilizer, etc.

3) Use an algaecide (PolyQuat 60) to prevent algae from growing and add it weekly.

4) Maintain proper disinfecting chlorine levels (enough chlorine for the pool's CYA level).

Option #4 is generally the easiest thing to do and is what is promoted on this pool forum. Since you have to have chlorine anyway for disinfection, you might as well just maintain its level to prevent algae growth and not have to add anything else.

Richard

[iwannapool]

So how can one reduce CH besides draining water off and replacing with water that contains no/little calcium?

[waterbear]

I thought I read somewhere you could lower CH by slowly adding trisodium phosphate. I believe this is the common cleaning product, TSP.

TSP (the real stuff, not the substitue) has been used to lower calcium levels in pool in the past but is not commomly used anymore since the result of it is usually an algae bloom because the pool is now filled with orthophosphates! We are talking about REALLY HIGH phosphate levels! Back in the day I believe they hit the pools with copper afterward to keep the algae at bay.