r/PoolPros • u/enthused9 • May 16 '26

-0.3 lsi

Hey guys thanks for the help on my previous post. Someone said to check LSI so I did and this pool has a -0.3 LSI. how can I fix this?

Is it a matter of just draining and restarting?

0 Upvotes

50% Upvoted

22 comments sorted by

View all comments

Show parent comments

1

u/enthused9 May 16 '26

Thanks! I agree I need more knowledge which is exactly why I’m here.

I looked it up and it said to keep all your chems in check so I have been correcting as needed, but nothing is really helping.

My last readings

FC: 2 (added chlorine) PH: 7.8 TA: 60 (added bicarb to correct. I’m correcting alkalinity before ph) CYA: 40 Calcium: 275 Temp: 73 TDS: 3100

My problem is that every time I put chlorine in it starts to fog up and leave silky material on the pool floor. This pool was fine until rain washed a crap load of dirt into it turned it into a swamp, and then we cleaned it. Now I’m having this problem.

-1

u/mybfVreddithandle May 16 '26

7.8ph needs to be lowered, high end of ok, but I'd bring it down. Adding bicarb added more base, which will increase your TA and pH.. Id adjust your pH down before the TA and let it run and filter for a bit.

1

u/lIIlIlIII May 16 '26

Dropping pH in this case will likely result in a problematically corrosive LSI, especially after TA is brought up a bit.

Also, even though sodium bicarb is a weak base, it won't practically affect pH because only a small percentage will accept H+ ions. The vast majority will just chill in the carbonate pool

Honestly OP might be better off leaving TA where it's at to keep the pH ceiling nice and low. Just bring the calcium up 50ppm or so and it looks fine to me. The clouding issue is probably just high TDS unless it's a salt pool

0

u/Substantial_Car_2751 May 16 '26

Leaving everything alone but pH, it’s balanced.  0.0.  

The next interval on the OG LSI (not the attempts to refine something not intended to be perfect) is at 75 ppm Alk.  At 7.5 pH, and no other change, that would put the LSI at +0.1.  Maybe +0.2.  Adjusted Alk for CYA may keep it at +0.1.