Reoccurring green algea

[mknauss]

If you add water at the top of the pool, you want it to enter the pool as quietly as possible. By putting the hose in the skimmer, the water disperses into the pool at the surface with little disturbance.

 

[mgtfp]

If the CYA is this high shouldn't there be some chlorine showing when I test instead of the zero reading I got when testing today?

I think it's probably clear by now, but I thought it's still worth pointing out: The chlorine you add via Trichlor-tabs is a consumable, once chlorine has done its job killing algae and germs, it gets turned into salt and no longer shows in the chlorine test.

The CYA you add via Trichlor-tabs stays for good until water gets replaced. There is a very slow CYA degradation in hot climates, but this is by far too slow to compensate the intake of CYA by regular Trichlor use.

 

[Oasisdave2]

Ok Ch and Salinity readings are complete:
Pool Water:
PWT - 84
CH - 650
Salinity - 1100

Refill Water:
FWT - 80
CH - 125
Salinity - 249

I'm not sure if I really understand how to do the Delta Calculations though. Is it PWT minus Pool TDS then Divide and then do the same with the fill water?

 

[Oasisdave2]

Water exchange has been completed, I added 1.3 gallons of 10% Chlorine and after a couple hours here are the initial test results:

FC - 5.5
CC - 0.5
CH - 150
TA - 160
CYA - 0
PH - 8.2

I added some Muriatic acid to bring down the PH a little and currently have a sock with a little over a pound of conditioner in it. Instructions say that 1lb per 3000 gallons to get a CYA of 40. I'm planning on raising the CYA a little at a time with the hope of doing a SLAM this coming weekend since there was residual algae after the water exchange. Does that sound like a reasonable plan to you guys? Any suggestions or anything I'm missing?

Also thanks to everyone for the guidance and advice

 

[mknauss]

Does that sound like a reasonable plan to you guys? Any suggestions or anything I'm missing?

Yes.
Do not go too slow on the stabilizer. You need 30 ppm in the pool water soon otherwise the FC will disappear during the day very rapidly.

 

[Oasisdave2]

Yes.
Do not go too slow on the stabilizer. You need 30 ppm in the pool water soon otherwise the FC will disappear during the day very rapidly.

Sounds good, should I be worried or do anything about the low CH and high TA. I have a spillway from my spa.to.the pool which I guess will hopefully gradually help lower the TA. Do I need to get some calcium chloride to raise it or should I wait until after I've got the CYA where it needs to be and the SLAM completed?

 

[mknauss]

The CH can wait as long as the TA and pH are a bit elevated.
I ran the CSI with your data and it is fine for now. Do not lower the pH below 7.6 or so and it will be fine without raising the CH.

I am surprised your CH is only 150 ppm. Colorado River water is 250 ppm. I assumed your water source is from there.

 

[Oasisdave2]

I'm surprised your CH is only 150 ppm. Colorado River water is 250 ppm. I assumed your water source is from there.

Yeah I really don't know why that would be. EMWD our water supplier calls our water recycled water and apparently add 'free Chlorine' whatever that is so maybe it lowers the CH somehow?

 

[mknauss]

They add chlorine to the water. Does nothing to CH.

 

[Oasisdave2]

Ok here are the latest tests results, I didn't get a chance to SLAM last weekend so.am looking to start this Friday when I get home from work.

FC - 5.5
CC - 0.5
TC - 6.0
CH - 150
TA - 120
PH - 7.5
CYA - 50

Is there anything I should try to adjust before the SLAM?

 

[IceShadow]

Good to lower pH to 7.2 with acid, then SLAM away!