I'm new to TFP and to pool care in general. I bought a home with a pool in August and learned just enough to keep it up until closing. I'm so happy to have found this forum and the Pool School. I've learned so much over the past couple weeks.
Here are my current test results:
FC = 0
PH = <6.8, my test was light yellow. It's likely lower than that.
TA = 0
CH = 110 ppm
CYA = 100 ppm or greater - my test kit doesn't test higher than this, but I learned today about testing diluted pool water to get a more accurate reading. I will try that tomorrow hopefully and update.
For some added info, in my area, we get a good amount of rain, so it is common to need to lower the pool level regularly.
I just took my winter cover off the pool to see that it's green with a nice algae bloom. I wasn't too panicked, because it doesn't look too bad and I know that SLAMing and cleaning it carefully should take care of it. But my high CYA levels means I'm going have to use a TON of chlorine to do it. I believe the former owner used trichlor tablets (cal hypo) exclusively for eight years, and it's clearly taken its toll, though I was glad to see the CH level isn't too bad.
My questions: Should I go ahead and SLAM the pool now even with the high CYA level or should I replace water to lower the CYA level first? If the former, at what point should I take care of the CYA problem?
Side questions: My pool does not have a drain at the bottom, so I'll have to drain it from through the skimmer. Given that, would the proper process be to drain it down to the bottom of the skimmer, refill, and repeat until CYA level lowers to normal range? Or do I need to find another way to drain the pool?
Thank you in advance.
This morning, I did the CYA test twice with half pool water and half tap water and got some much more encouraging results. Both times I found that my CYA level is only at 80 ppm, not at >100 ppm. Last time was my first time doing the test and I think I fluffed it. I didn't have very good light and I think I stopped pouring too soon. It's the kind of test where you pour a solution of reagent and pool water into a tube until the black dot at the bottom disappears.
It's still much higher than I would like but at least it's not over 100 ppm like I thought. It will be much easier to fix this with replacing water. Pool Math says replacing 50% of the water will bring it down to 40 ppm and 38% will bring it to 50 ppm.
It would seem that despite the former owner using trichlor tablets, the CYA level didn't get too out of control. This is likely because we get so much rain in my region that the water is replaced naturally more often than in dryer regions.
I'm going to try to start draining today if I can.
UPDATE 5/10, evening:
The siphon worked like a charm today. Thank you to all for that suggestion and for help on how to do it. I drained a little less than half the pool water and I'm currently refilling it. That probably won't be done until tomorrow afternoon. I'll then let the water circulate a bit before testing and post new test results. I hope this works!
I finished refilling the water, let it circulate for a few hours and tested. My CYA went down to 40 ppm! I was a little surprised to see my CH didn't change, but it's only at 110 ppm, so that's okay. I'm so relieved this worked. Now I just need to raise my TA, then my PH and then SLAM and clean the pool so I can get swimming! Thank you all for your great advice and support. Test results below:
CYA - 40 ppm !!
CH - 110 ppm
PH - <6.8 - probably much lower
TA - 0 ppm
UPDATE 5/15 -
With advice on another thread, I was able to get my other levels stabilized and my first SLAM has gone surprisingly well. I think I was able to vacuum most of my algae out to waste and the rest was taken care of within the first night and day after adding shock. I passed an OCLT test last night, my CC is at or near 0, and the water is quite clear. Thank you all so much for your advice and encouragement. I'm so glad to have found such kind people on this great forum!