New Pool Balance

Hi I have a new pool, it was finished 5th October and contain about 10,000 gallon of water. The pool is plastered with florida gem, and is going to be a salt water system but we have not yet put salt in and are using a chlorine tablet floater and chlorine bleach to keep the chlorine up this seems to be fairly stable.

My problem is that we have a calcium hardness of 320, we use rain water and Ro water so was surpirsed by this but on testing our rain water tanks we discovered that they contain calcium. we have no supply usable to lower calcium.
PH is currently 7.2 but does seem to change a bit
Alkalinity is 40

Taylors water gram is telling me that the water is reasonably balanced but everything I read says that the alkalinity should be between 80 and 120 , every time I try to get the alkalinity up the PH goes up and if I use muriatic acid to bring down the ph the alkalinity goes down. Am somewhat confused.

1 - If the water gram says the water is balanced is that ok?
2 - If my alkalinity stays at 40 will my ph be stable?

would appreciate any advice, we will need someone to look after the pool when we are not here and want everything sorted before I try to get a local to take over.

Thanks for any advice it will be much appreciated

Hi!

First off, with a plaster pool, a CH of 320 is well within the recommended range of 200 to 400ppm. So you're fine

pH and Total Alkalinity are linked. pH goes, up, TA goes up. pH goes down, TA goes down. If your pH is stable, I wouldn't worry too much about your TA. However, the BEST way to raise TA with minimal change in pH is to add ordinary Arm&Hammer or generic baking soda. That's all pool store Total Alkalinity Raiser is--baking soda. pH will probably go up, but when you lower the pH the TA won't go down as much. That's how you get around that link (there's a different, more complicated one to LOWER TA, but you don't need that).

If your chlorine tab is what most are, Tri-Chlor, then it's EXTREMELY acid and will lower your pH. Meanwhile, a new plaster pool as it cures will raise pH. So as long as your pH is between 7.2 and 7.8 I wouldn't adjust it.

Tri-chlor will also add CYA, aka Stabilizer. You need it to keep your chlorine for disappearing too fast but too much is also problematic. Check out our "Best Guess" table for optimal levels of Chlorine vs CYA.

Thanks Carl

the ph is creeping up and a little muriatic acid brings it within range, but I think I will try the bicarb first to bring up the alkalinity and cope with the resulting ph rise in the hope as you say the alkalinity will not drop back to the lower level, especially if I modify the ph a little at a time.

thanks for your response.

Lindy

Membership updated.

I just saw that your pool is in the Bahamas. Which island?

You'll need to get a good, proper test kit. I don't know if you can legally bring a Taylor K-2006 or K-2006C in, or if it's available (if so, probably only in Nassau). If you can bring it in (in checked luggage), you'll know that duty on it will be between 40%-60%. But I've not looked into what pool supplies and test kits are available in the Bahamas because when we're there, our pool is....the ocean! (VERY low maintenance!)

There are strategies for pool care when you're not there, though, of course, the best is someone like our members who know the B-B-B system well and are comfortable with it. Still, if you're away for 2 weeks, I'll just have someone dump a certain amount of bleach in every other day. Now that I'm away longer, I have an SWCG so it's able to stand low or no maintenance for longer periods of time.

But if you're gone for months at a time, well, that's beyond my experience.

The pool is on the North End of Elbow Cay, we are very lucky we now have a choice of an Atlantic beach 200 yds on one side, an Abaco sea beach 200 yds on the other side and a pool in the middle. Am still taken with the new pool and have only been swimming from the beach twice in the last week. Have made a note to self to make sure I don't forget the beaches they are fantastic and as you said maintenance free. I guess we probably would have not put a pool in but we rent the house and need to up the rentals. On the plus side when we are in the Bahamas and the house is rented we live on a boat and are surrounded by the biggest pool with no maintenance requirements.

Which island is your house on?

We have put in a SWCG but are just trying to get this balanced. We put in the salt two days ago, pool was balanced according to Taylors water gram before I put in the salt. PH keeps rising, I put in 2lb bicarb yesterday to try to bring up the alkalinity which was between 40 and 50 ppm.

I am trying to find a source for borax to put that in, I am guessing that I will always have a problem with alkalinity due to the water here which is either rain water or RO water and from what I have read the borax will help with PH. I have put in CYA and was using household bleach and a floater with a tablet in which I believe will add CYA.

I am going to do a complete set of tests today and will post results.

I can get most pool chemicals here from the main island.

My test kit is a Taylors complete kit chlorine DPD we bought from Leslies in Fort Lauderdale but cannot find any code to match your recommended code so I am not sure if I I have anything missing.

It uses two test tubes effectively and I use drop counts for alkalinity, calcium hardness and to test for acid demand, but use colour match for chlorine and initial PH reading. There is also a CYA test which involves a black spot disappearing at the bottom of the smaller test tube.

We are going to have someone check the pool once a week when we are not here as we are missing 2 or 3 months at a time and I was going to bag up bicarb or just buy 1lb and 1/2 lb boxes with instructions on what to do.

I will post the results once I have them.

I do have one question

Which is first to correct

Alkalinity or PH

I need to do the best I can in terms of balance before I have to leave on the 11 November and then hope the pool lad we will be using can cope until we get back in Feb next year.

Wow! Lots of questions. We're on Abaco itself, south of Marsh Harbour. Easier to get to! (as you know) Been out to Hopetown a couple of times. Elbow Cay is very beautiful. Not sure what pool stuff is available at Abaco Hardware or Standard Hardware, though they have it for people who have hot tubs, etc. nor if Maxwell's supermarket has Borax. I'll need to look next time we're there in a couple of weeks.

You can easily upgrade your current test kit to the equivalent of the K-2006 by ordering the K-1515A or K-1515C from Taylor Technologies. It's the FAS-DPD chlorine test, rather than the DPD test, and it's the best test you can reasonably get for testing Free, Combined and Total chlorine.

SWCGs are notorious for raising pH. I'd suggest you leave your TA nice and low to counter the rising pH and NOT try to raise it. You should also cover the pool when not using it to prevent aeration and gassing off--which raises pH (and is part of our lowering-TA procedure).

Borax is for adjusting, not buffering pH. What it DOES do, is helps control algae when borates reach about 50ppm. Otherwise, it's what you add to raise pH.

You'll want to get your CYA up to 60 to 80 ppm, because that's what most SWCG manufacturers recommend, and, in the Abaco archipelago, chlorine demand will probably be high so the higher CYA will help control that.

For your last question, I'd leave TA where it is and control pH.

Enjoy it! It's like paradise!