Commercial Sized Personal Pool

[Kseaton13]

I care for a 55,000 gallon pool with a smaller hot tub attached. The pool system is 7 pumps with two DE filters, multiple cartridge filters. The hot tub spills into the pool from elevation during normal operation. The pool is salt water.

We took over the pool management and slowly the pool has started to get a "smokers yellow" tinge. It also has black algae spots that come and go with seasons. The pool was a white/blue color previously. We have tried a number of solutions to fix this issue and one that worked in the spa was isolating the spa and extreme shocking it however it did not last as a solution for long. At one point we managed to turn the spa purple which we thought implied there might be copper residue in the water. We got citric acid and added that today in powder form but the acid only affected the areas it touched and settled. Otherwise it didn't do anything.

We also have "super shocked" the main pool which is putting about 30 gallons of chlorine in it and that did not affect the color. Within two days all pool levels were completely normal again so I do not know if that was simply not enough chlorine. We do not want to waste chemical but we do need something to return it to the original clarity on the walls.

Any suggestions would be great and if more information is needed, please let me know so I can clarify. Thank you so much.

 

[Chemnut]

I doubt anyone can help until we know your treatment routine and testing results.

 

[Silver_2000]

4 or more filters seems excessive for a pool that is 2-2.5 times the size of a typical pool with one filter

I have 5 pumps on mine but only due to crazy owner builder before me - one pump powers the one filter

 

[Jimrahbe]

K,

Welcome to TFP... A Great resource for all pool owners, even those with Big Big pools...

Please tell us more... we would be interested in what type of Salt Cell(s) you have... That will make a huge difference in how the pool will be able to work...

How many cells do you have and how long do you run them?

Do you have any idea what your CYA level is?

Thanks for posting,

Jim R.

 

[YippeeSkippy]

I'm more curious in how you test the water?
Can you tell us:
FC
CC
pH
TA
CH
CYA
Salt Level

Those will help us enormously! You say its a salt water pool, but is it chlorinated with a SWG or just has salt in the water for comfort?

Also what else have you put in the water? Any algaecides with copper? What else?

Maddie

 

[PoolGate]

My guess is a very high CYA (cyanuric acid) level which is rendering the Chlorine ineffective. You need to test for CYA levels. If that is the case the only solution is to drain and replace some water.

 

[Swampwoman]

Kseatin, is this pool on well?

You're theory on copper cyanurate from high cya and copper in the spa would be a good one but that interactin usually happens in colder water. Maganese can also cause purplish stains.

Yellowing water in a chlorine pool to me usually suggests iron that has oxidized from high FC level. A HEDP metal sequestrant would sequester in this case.

What do you use for testing?
At TFP, we reccomend a FAS/DPD kit such as TFT 100 or Taylor k2006 specifically ( TFTestkits.net ) but if you're using a meter the important thing will be that it can read high FC values.

Citric acid is less preferable in metal strategies compared with Ascorbic Acid due to the byproducts it forms. With that said, it might lighten stains on contact but doesn't in itself sequester copper. You'd need to follow up with sequestrant. Sulfamic acid works better as a copper stain treatment, but again, does not sequester.

So to get to the root of metal problems, the first step is to get the regular chemistry balanced and sorted. For example, ph should be maintained at a lower level if there are metals in the water, eg 7.2-7.4.

Post up a complete set of regular results and we can help untangle the case of the very large mystery pool