CH for new pebble finish pool - sudden high CYA and now algae

rnjw

Bronze Supporter
LifeTime Supporter
May 19, 2014
34
Pittsburg, CA
My pool builder is recommending 200 for CH but Pool Math indicates 250-300 or more. What should CH range be to not damage the stone or grout and tile? new pebble pool.jpgReread the info about CSI and attempting to follow all details.

Maintaining with TFP liquid chlorine (Kem-Tek from Lowes)
We are now experiencing water temps of 82-85 degrees. Chlorine is 3-6, Ph steady 7.3 - 7.5, CH at 150 and slowly adding to get to the 200. CYA has been around 35-45.

Very high winds for several days so I neglected checking and allowed Cl to get to zero. Algae was hard to see and wrobgly assumed our new Dolphin S200 would clean all walls and floor- except the steps.
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
30,848
Laughlin, NV
What is your fill water CH? If 100 or above, I would not add any more calcium as your fill water will increase it as you fill from evaporation. If your fill water is less than CH 100, I would raise CH to at least 250ppm.

Be sure you follow the FC/CYA Chart. If you see visible algae, follow the SLAM Process
 

rnjw

Bronze Supporter
LifeTime Supporter
May 19, 2014
34
Pittsburg, CA
Just measured incoming (house) water and it is 100. I don't top off the pool very often but wait until it is 1/2 -1" down.
More disturbing today is finding CYA at 70 suddenly. Checked it twice. It has been around 45.

I also did some brushing, not just the steps, and find algae on all the walls. I believe my test kit chemicals are ok.

Stuey, the Dolphin S200, is in the pool now while I decide to go ahead with a Slam after I figure out how much CL to put in.

Background: pool has been covered every night, the few leaves and blossoms either skimmed or picked up by the Dol[phin. Water temp has been 82-85. Windy. Only 2 of us swimming for about 30 minutes a day, no sunscreen or other chemicals..
 

rnjw

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LifeTime Supporter
May 19, 2014
34
Pittsburg, CA
Reading old threads, I belie6an algae bloom hit me. Cya between 45-60, CH now 200. I used kemtek chlorine and brought it up to 14-15. Pool covered overnight but timer on so only ran 5 hours instead of continuous.

After 2 days at 13, I left it open and brushed what I assume was dead algae off the walls and vacuumed it all up. Added water and was finally down to 7-8 ppm Cl. CH still at 200, added a little muriatic to bring Ph to 7.5.

A couple more days and now maintaining 4.5 Cl by adding a out 8oz every night. Pool is clear but brushed a little algae off one corner and shallow end.