Should I raise calcium levels?

[EastCoastDigs]

Hello all,

We have opened our pool this week and have it balanced, mostly. However, I am seeing some raised bumps on the bottom of the pool surface. We have had these before. I've always been confused on whats scaling, etching, deposits, etc. I can't find photographic examples to better understand. Anyhow, I'm wondering if I need to add calcium and if so to what level.

17,000 gallons plaster pool In Virginia
Temp of water is probably low 60s.
Ph 7.4
AL 60
Cya 40
CL 11
CH 275 / 300 (I got two different readings)
Testing with the TFP Pro.

Thanks for the advice!

 

[ajw22]

Ch of 275-300 is fine. Whatever your problem is adding calcium is not the answer.

Sounds like it may be calcium nodules. Pics in...

Calcium Nodules in pools

What are calcium nodules? In swimming pools and spas, they are small mounds, bumps, deposits, or “slag” piles of calcium carbonate which are formed from material that has been released from the plaster. The small calcium nodules are rough to the touch, hard, and generally gritty. Nodules may...

www.troublefreepool.com

Plaster Installation and Maintenance - Further Reading

www.troublefreepool.com

 

[EastCoastDigs]

I can't get a good photo of the bumps, but there are about 6 small areas in the shallow end. About 1-2 inches in diameter at the base and they are rough and raised about .5-1 inch. They also appear to be dirty as in tinted brown, probably because of the winter staining from leaves, dead bugs and what not. There is a spot on the side of the deep end that is a thin raised white line about 12" long and rough.

 

[ajw22]

I can't get a good photo of the bumps, but there are about 6 small areas in the shallow end. About 1-2 inches in diameter at the base and they are rough and raised about .5-1 inch. They also appear to be dirty as in tinted brown, probably because of the winter staining from leaves, dead bugs and what not. There is a spot on the side of the deep end that is a thin raised white line about 12" long and rough.

Sounds like calcium nodules.

 

[EastCoastDigs]

ajw22, thank you for this information. That write up is so helpful and it does sound like what I may be dealing with. This pool is likely from the mid 70s and probably was replastered at some point. We can't be sure. We have owned it about 8 years.