I am a pool virgin setting up a virgin pool. Water has been in a couple of weeks and I have been using the forums and the Pool Calculator to educate myself and work on getting the water chemistry as it should be. A big thank you to all who contribute to these resources.
Pool is an infinity lap pool with a 65' edge and a SWG, about 20,000 gallons. It is fully tiled with 1" tiles, so lots of grout. It is outside and in full sun (most days) from about 10.00 am to sunset. I have no access to pool chemicals locally (hence 0 CYA at this time), so I have been using only Clorox and muriatic acid so far. I am ordering a shipment of pool chemicals and will follow Pool Calculator recommendations re CYA once they arrive in 2-3 weeks time. Will probably also add Borax at some point. Currently running VS3050 on speed 2, 24/7, chlorinator at 50% in daylight hours, and adding about 1.5 quarts bleach every night. As there is no CYA, chlorine is usually less than 1 by morning and does not register later in the day, but pool is staying clear and sparkling so far.
My question concerns the calcium level I should be targeting. Current numbers are:
Everywhere seems to suggest I should be aiming for a CH level of at least 250, but after playing with the numbers in the Pool Calculator (PC) I am wondering if this is really right for me. The SWG and the need to circulate the trough water over the long infinity edge from time to time to keep the trough sanitized are going to result in high PH levels as I understand it, and I am thinking it likely that it will be easier to operate with a target PH of 7.8 or even 8. With a PH of 8 and the numbers above, the PC gives me a CSI of 0.19 ('Balanced'). Raising the CH to 250 changes the CSI to 0.5 ('Potential to become scaling'), so why might I want to raise the CH? My understanding is that the higher CH is to protect the plaster (in my case grout), but if the CSI remains within the OK range then surely that is not a concern? It seems to me that leaving the CH where it is gives me more leeway on a high PH....?
Once the chemicals arrive, I am thinking CYA 70, TA 60, CH ??, and PH where it settles, as long as the CSI is within range. Obviously I will have to add muriatic from time to time, but I am seeking to minimize acid use. I would welcome comments.
If any of the gurus on the site would like me to run any experiments on a pool with truly 0 CYA then let me know. I am currently using a Taylor 2005 test kit so accuracy of measurements of chlorine levels is currently limited by color matching, but I plan to bring in a 2006 test kit with the chemicals.