replaster start-up

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Pump has been running 48 hrs now, TA 100, pH 7.4, CH 325, water crystal clear. I have pvc "aerators" on the return lines instead of the eyeballs to raise the pH a bit. I'm concerned about algae growth, in this thread http://www.troublefreepool.com/content/154-start-up-new-pool-plaster it says to raise the chlorine slowly after 48 hrs of circulation, would that be something like a quart or two an hour into the flow of the return/aerator flow?

thanks, Brian
 
Normally you can put one 7 or 8 oz trichlor tablet in the skimmer for each 10,000 gallons, replacing them just before the old ones dissolve, and that will take care of it. The resulting FC level will be fairly low for the first few days, but the CYA level will also be quite low so the FC level should be sufficient. That gets you a smooth gradual rise in both FC and CYA levels, which is good.
 
Since this morning my TA climbed from 100 to 130, pH from 7.4 to 7.7. Using pool math I'm going to add 43oz( qt, 1 cup, 3oz) to get the pH down to 7.2, then continue to aerate to gain pH level. Let me know if this isn't correct but it seems pretty straight forward.

thanks, Brian
 
As you described, you should do a little more aeration/acid, which will get the TA down a bit more. After not very long you will catch up and the acid needed to keep PH in line will keep the TA in line as well without any more aeration.
 
Well.....another factor enters the picture, my pump started leaking and the pressure dropped from 8lbs when I first turned it on to about 3 now, still moving water but not a lot. Question is will I be ok by putting a couple of sump pumps I have(suspended in the water) and do a lot of brushing until I get the pump issue sorted out?
I'll ask about the pump in a different area of TFP, I'm concerned about the pool chemistry since its a replaster start-up.

thanks, Brian
 
Yes, a sump pump (or two) will provide enough circulation for a couple of days. You will want to move the trichlor tablets to somewhere a pump is running water over them. Try not to go more than a few days this way, things start to get questionable after a week or so without full circulation.
 
Yes, got the pump working again. After one 24hr period of having a fully functional pump my readings were:

TA 130
pH 7.5
FC 4.5
CC 0.0
CH 325
CYA 0.0

These were taken yesterday(mar 29) afternoon around 3pm. After the reading I used Pool Math and added 41oz of ma to get the pH down to 7.0 and then ran the pump/filter with two water return pvc aerators(moving a lot of water with the pvc above pool level causing a lot of splashing) overnight and checked again at 6:30 this morning. The pH was up to 7.7, TA 90, both really close to what I want.

CYA I've had 3" trichlor pucks in skimmer(in a floater), used up one, the second about 3/4 gone but still no cya registering. To keep the chlorine level above 3 I've added a lot of liquid chlorine(most likely the sun is eating a lot, at this time no one is using the pool), over a gallon a day. Can I add stabilizer through the skimmer using the sock method or premixing the dry stabilizer with water and pouring into the skimmer now? I'd really like to get the cya into the water so I can back off on adding so much chlorine. Pool Math says I need 2.5lbs to get to 30 from 0. Since I don't want the cya too high should I put 1/2 of that(1.25lbs) and then take a reading after a few days? Will premixing with water get the cya levels up faster than the sock method and is there a downside to premixing?

Also regarding cya levels into the recommended 30-50 range. Why would I want to have cya higher than 30, since at that level I would need to use less chlorine than at 50?



thanks, Brian
 
If you use an average of one 7 or 8 oz trichlor tablet for every 10,000 gallons of water, and replace them regularly the FC and CYA levels should track each other appropriately. When CYA levels are low, the FC level you use can also be low. Keeping FC at 3 when CYA measures as zero is not required.

The CYA test can't measure any CYA level below about 20, and will simply report lower levels as zero. If you are using tablets, your CYA level is going up and will eventually get into range.

CYA and chlorine levels can be a little tricky. The key to understanding is that FC levels and the amount of chlorine needed to maintain that level are two different things. At lower CYA levels you maintain a lower FC level, but need to use more added chlorine to maintain that level.Thus, at higher CYA levels you will be spending less on chlorine, even though there will be more chlorine in the pool.
 

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JasonLion said:
If you use an average of one 7 or 8 oz trichlor tablet for every 10,000 gallons of water, and replace them regularly the FC and CYA levels should track each other appropriately. When CYA levels are low, the FC level you use can also be low. Keeping FC at 3 when CYA measures as zero is not required.

The CYA test can't measure any CYA level below about 20, and will simply report lower levels as zero. If you are using tablets, your CYA level is going up and will eventually get into range.

CYA and chlorine levels can be a little tricky. The key to understanding is that FC levels and the amount of chlorine needed to maintain that level are two different things. At lower CYA levels you maintain a lower FC level, but need to use more added chlorine to maintain that level.Thus, at higher CYA levels you will be spending less on chlorine, even though there will be more chlorine in the pool.
Click to expand...

If I understand correctly the tabs are adding cya but not to a measurable level at this time, so to add more(as by the sock or premix method) at this time could increase cya too much without me realizing it, correct? So for now I'll just measure the chlorine and add as per Pool Math to keep it at 2 or so until I get a cya number thats measurable.

"at higher CYA levels you will be spending less on chlorine, even though there will be more chlorine in the pool"
Great, I think I'm getting closer to understanding what's going on in my pool.

thanks for the info, its a big help,

Brian
 
These readings were taken at about 6:30am today:

FC - 3
CC - 0
pH - 7.7
TA -100-110
CH -350
CYA -0

I'm running my pump 4hrs day, usually from 6:30-8:30AM and 7-9PM. I've had the trichlor tabs in the skimmer(one at a time, about 30% left of the 3rd tab now) and as the tests show still 0 CYA. As the result of no CYA I am losing just about all of the chorine(I suspect mostly from sun loss) I put in the pool every day; AM readings are usually 3-4(from adding chorine as per Pool Math the previous evening) and PM readings consistently 0-.5.

Although you suggest letting the CYA rise slowly from the tabs it seems like this is taking way too long, necessitating the addition of at least 2qts of chlorine daily to have any left by late afternoon. What harm will it do to add the CYA(in the form of powder in a sock in the skimmer) to introduce it into the water at a faster pace?

I'm brushing twice a day, in the morning and evening, and water is crystal clear.

One other question: I have not backwashed the filter since the pool was plastered and filled, should I do so now to get rid of any plaster dust in the filter(if it collects there or is dissolved by the acid I don't know) but to date the pump pressure has remained a constant 14-15lbs. I am still adding a cup or so of acid a day(as per Pool Math) to keep the pH in the 7.6-7.8 range, which I believe is normal for a new re-plaster job.

thanks, Brian
 
For about the first week after plaster is applied you want to be very careful about what chemicals you add, so I wouldn't add any CYA other than from the tablets during that period. After a week you can add more chemicals manually if you want, just keep the increases fairly gentle, i.e. don't jump up to your full target CYA level right at the one week mark. Also keep in mind that PH, TA, and CH levels will continue to increase on their own for the first month or so. After three or four weeks there is nothing to worry about at all and you can treat the pool normally (except that it will want some acid regularly for up to a year).
 
From pool math: Note: It can take solid stabilizer up to a week to dissolve.

Is this referring to solid as in tablets or does it include granular? I started adding cya in granular form today, 1 1/2 lb, put it in little by little in front of the deep end return with the pump running, brushed until it disappeared, repeat until it was all dissolved. I'll take a reading tomorrow, should this show up? My target is 50ppm, Pool Math says 6lb 1oz. Should I repeat this process daily or is that to rapid?

thanks, Brian
 
Which would be a better cya level, 40 or 50ppm? From my reading on TFP they seem to be pretty close as far as effectiveness and/or chemical costs go. My pool gets full sun most of the day, generally little use(my wife and I for short periods during the day) with an occasional "pool party" once or so a month. The pool is generally covered with an opaque cover. I'll shoot for 40 initially as I can always raise it.

thanks, Brian
 
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