Latest levels post simultaneous partial drain/fill... Gonna hold here
Alright, now that I have wasted way too much water doing this simultaneous partial drain/fill, I got my levels this AM. While I knew this was necessary, it was just unfortunate having to use so so much water, and waste a very good amount down our home's sewer clean out. Our landscaping could only hold so much. Anyhow, what's done is done. Here are my latest levels:
Chlorine via OTO test: 5 (wanted to do this to see how it read compared to the FAS-DPD)
pH: 8.0
FC via FAS-DPD test: 5
forgot to test CC, but based on my last full testing it was 0
using above results, TC most likely 5
CH 900
TA 180
CYA 50
I am thinking about holding at these levels. I was doing a lot of reading early this AM regarding the best CYA level. I found some very in depth posts from Chem Geek and Mas985 (not sure if the later is right) regarding CYA levels and chlorine extinction vs. protection with sun exposure. Above what I was hoping to find. Basically, what I learned from the posts was that a level of 30-50 with a pool that is exposed to a good amount of sun may not be the proper level. The lower I go on my CYA, the faster my chlorine will get burned off/used from the sun. Thus, even though I would have to use slightly more chlorine by keeping a CYA level at 50, for example, than at 30, maintaining a level at 50 may be better suited for my pool d/t the sun exposure in Livermore, CA. Our pool is pretty much totally exposed from 1000 to 1800 hr, if not longer. In fact, in the ABCs of water chemistry in Pool School, it reads "If you have a SWG or very high levels of direct sunlight, CYA is typically kept between 70 and 80." Hence, while I was originally shooting to bring the CYA to 40, that may not have been a good goal. Therefore, I am thinking that perhaps 50 is good for now. I guess you want a CYA level that offers the chlorine protection from the sun, but is not so high that you have to use so much chlorine to maintain it. Can anyone chime in on this?
Kind of strange that my TA is 180 after all this, as my other post on my levels revealed it was lower. But, I have done a lot more water replacement since then, so perhaps it could actually read higher. According to the CSI on the Pool Calculator, I can manage with a CH of 900 and have balanced water if I manage my other parameters. It revealed that if I maintain a pH of 7.3, TA 80, CH 900, CYA 50 (using a water temp of 75) that my CSI would be 0.04. To achieve this, I am going to lower my pH to 7.0 using 292 oz. of 14.5% MA, point as many of my returns up to the surface, and then retest tomorrow. How long do I need to keep the pump running after adding this much acid in order to bring down the TA? I understand that for mixing typically the pump needs to be run for 1 hr for liquids, but in the case of pouring in extra MA to lower the pH, I am not sure if I need to run it longer.
Tx for all the help along the way with this. I will say that the water is ridiculously clear! Additionally, it feels good knowing that I am managing it. I am grateful for all the help I have received and all the superb information that this site provides.
Anyhow, they are as follows (I question my results w/ the CH as I did not know what shade of blue I was supposed to see; and I kind of lost count of when the water changed to blue, but I know the amount of drops was in the 50s or at 60; I have already been told previously by service techs my CH is >1000):
