Sanity Check

[lukeyluke]

Hi all

Just hoping for a general sanity check.

I have a fibre glass pool which I have confirmed to NOT have calcium in the gel coat.

Im currently running these numbers. Does this look like a safe pool balance? Just wanting to make sure I lool after the shell

PH:7.3
TA: 70
CYA: 40
CC: 0
FC: 5.5
CH: 70

One main question is in relation to the CH level. Knowing that the pool does not contain calcium, is a CH of 70 ok?

I have some fading right on the water line which im assuming is just UV / natural aging. Summers are extreme in Australia

Cheers all

 

[CRAD_oz]

Are you tracking your CSI?

 

[wireform]

You numbers look good except for the SWCG I like PH in the 7.6 range and 70 for the CYA. As Crad said watching the CSI would be be my go to reference.

 

[lukeyluke]

Thanks all. I do track my CSI it is -1.05. However due to my pool not having calcium in its construction the reading throws me. I feel that the CSI calculator does not take into account fiber glass pools with no calcium in the shell or gel coat.

Any thoughts or leave as is?

 

[wireform]

The recommended CSI is .6 to -.6, you can play with poolmath in the drop down menu called "effects of adding" to see what to tweak to bring the CSI in line.

 

[lukeyluke]

Do you think I should increase the CH a little? Having trouble getting the CSI in line without increasing the CH level. Very confused.

 

[CRAD_oz]

Luke
Have you read the Pool School ebook?
It list the reasons for the CH to be at a certain level for Fiberglass and for SWCG pools.

 

[CRAD_oz]

 

[lukeyluke]

Thanks Crad. Actually went back to the owners manual for the pool and they basically say CH level of no more thank 150, and in the next sentence to not ever add calcium to the water.

Would a balanced approach here to simply increase the CH level to maybe 100-120ish and move on with my life

 

[CRAD_oz]

Hey Luke
I'm no expert but you may find it harder to keep your CSI in an acceptable range with your CH too low.
Play around with your numbers on Pool Math including your water temperature during winter and Summer.

 

[ajw22]

Low CSI does not matter on a fiberglass pool without any tile work. Low CSI is aggressive water that attacks plaster which you don't have.

High CSI is a concern as it can lead to scale. So for a FG pool don't worry about low CSI and the lack of calcium. Just keep your CSI below -0.3 and below scale territory.

The FG gelcoat may need CH for optimum longevity and that is different then what CSI affects.

 

[lukeyluke]

Thanks all, I have a very faint white line (right on the water line) and then the rest of the fibreglass above the waterline is dulled. The UV here is extremely harsh, would this likely be UV oxidation? My CH Levels have always been low and CSI is negative, so I doubt it's calcium scale.

Just getting paranoid here

 

[lukeyluke]

Must be UV I think,
The fiber glass wall below water level looks original colour (obviously it is wet)
The fiber glass wall above water level when wet looks original (albeit a little more dull)
CSI is low
CH is very low (and no calcium in Fiber Glass Shell or gelcoat)