New Plaster Startup - CSI to 0.5? How to reach

kchinger

Well-known member
Aug 20, 2017
325
Southeast PA
So I've read a bit on here and it looks like high CSI is good for new plaster (like, +0.5), through some studies that have been done. Obviously my PB doesn't read any of that scientific Darn and just does what they've done for decades, so I'm planning on mostly ignoring him because they're just gonna blame me for any plaster problems anyway, regardless of if I follow their instructions, which don't have startup values anyway, just general values (which I can get to a high CSI with and still follow their guidelines).

So I'm currently on day 2 (or maybe 1) (fill started two days ago and finished yesterday, I dunno how to count exactly).

Last night I did acid and calcium after my readings, aiming for 7.6 pH and 250 CH.

Readings this morning:
TA: 70
pH: 8.2+ (it's off the scale)
CH: 250

So my plan is to add acid to get to 7.6 since it goes up so fast anyway, and slowly add CH until I can get my CSI up towards +0.5?

Does this make sense? But to reach a CSI of +0.5, I need a LOT of CH, like 800 CH if the pH is 7.8, TA is 70, and temp is 70 (it's 68 or so right now).

And my instructions say brush once a day, I want the smoothest finish possible, is twice a day better or worse or unnecessary? I see lots of stuff between 1x to 4x a day for the first week, and then it varies after that. Why can't they just get together and actually get this right? You know they have scientists at these plaster companies who can figure all of this out precisely and give good instructions. Why is the pool industry so screwed up? (sorry, ranting)
 
What startup are you following….there are specific requirements here, don’t just add stuff.

e.g. This one from NPT….sure someone will give more info in a bit.


e.g. Pebbletec

 
Last edited:
What startup are you following….there are specific requirements here, don’t just add stuff.

Traditional.


They're pretty useless as far as chemicals go, so I've been piecing it together from the guide here plus NPT guide and stuff.
 
Do not raise your CH so much.

Do not take the +0.5 CSI target so literally since you cannot lock in a specific CSI number.

The message is that positive CSI is better for plaster curing then negative CSI. If reasonable water chemistry can get your CSI in the range of +0.2 to +0.3 then that is better then what most pool builders do.

What is the CH of your fill water?
 
Were you given that start up guide by your pool builder or is it some you just found on the net?
 
You can do a bicarb startup if you want.

My opinion is to do a balanced startup where you keep the CSI as close to 0.0 as possible.


 
Do not raise your CH so much.

Do not take the +0.5 CSI target so literally since you cannot lock in a specific CSI number.

The message is that positive CSI is better for plaster curing then negative CSI. If reasonable water chemistry can get your CSI in the range of +0.2 to +0.3 then that is better then what most pool builders do.

What is the CH of your fill water?

Fill is around 75 or so.
Were you given that start up guide by your pool builder or is it some you just found on the net?
It's from my PB. They've been pretty useless honestly. Use a bunch of subs for literally everything, never tell me what's happening, people just show up, and the plaster guys just tossed a hose in, left, and my builder had trucks here the next day. Nobody has been out to check or inspect or do any sort of anything, it's just "good luck".

I'm hoping it turns out fine (the plaster itself looks grayer than the samples, but we're hoping it cleans up I guess).
 
Brushing is not going to make your plaster smoother.

Brushing will keep the plaster dust from depositing on the pool surfaces and keep it in suspension so it can be filtered out. Otherwise the plaster dust can harden on pool surfaces and be rough.

Once per day is good. More brushing can’t hurt.
 
I would raise your CH to 350 and run your pH in the 7.6-7.8 range. Your water temp should rise over the next month which will raise your CSI.
 

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Thanks, yeah, I'd found their guide and was looking at a bit of it. However, if you follow their guide you can end up with a CSI of like -0.65 or lower, which seems pretty darn aggressive, I don't understand why they do that. They even understand what the LSI/CSI is, and talk about it after 28 days, but their initial chemistry is extremely harsh.
 
Water temperature has a big effect on LSI/CSI. You can only do so much with chemistry adjustments to offset colder water. So do the best you can.
 
Water temperature has a big effect on LSI/CSI. You can only do so much with chemistry adjustments to offset colder water. So do the best you can.
I'm not really getting any/much dust when I brush. Is this good/bad/indifferent? I just finished all the walls (need a break before I do the bottom) and I can still see the bottom fine, still see the main drains, it doesn't look much different. I was expecting big clouds I guess, lol.
 

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