Algae Problem, High CYA & CH - Need to Drain Pool

[mrs milty]

Hello,

I have had an algae problem for about a week now. I just got my Taylor K-2006 Test Kit yesterday. (You guys were right, pool store said they had one in stock, got there and it was a K-2005 DPD kit).

I have been using chlorine pucks on a regular basis and Pool Time 6-in-1 shock on a weekly basis. I did not discover your forum until 4 days ago, so, when the algae started getting bad, I added, and continued to add the Pool Time shock.....WRONG, I now know!?##!?

I had to rely on test strips up until yesterday, and they were showing my CYA level at about 150, with no FC, and a ph of about 6.8. I brought the ph up to 7.2 and have been adding 4-5 gallons of 10% liquid chlorine every evening, brushing and vacuuming a lot, and running the pump 24 hrs a day, keeping the filters clean. This has improved the algae situation.

Now that I have the test kit, I can make better use of the pool calculator.

Last night at 6:30 my test results were:
FC - .6 ppm
CC - .6 ppm
CYA - 200'ish guesstimate (the tube markings only go to 100, the black dot disappeared after about 1/2" of water added to tube). BAD
CH - 1100
ph - 6.2
TA - 100

I added 4.5 gallons of 10% chlorine
I did not have anything to bring the ph level up (????? is the reading even correct if I've been adding 4-5 gallons of chlorine everyday and with the current readings, below, do I need to be concerned about ph right now)?

This morning at 6:30 my test results were:

FC - 24ppm
CC - .4 ppm

Do I need to even test the ph & TA during this process?

The algae problem is slowly improving.

OK........so finally, here is my question:

Obviously, I need to drain the pool. (RO is out of the question, because the two RO companies are backed up until mid-July). I live inland in San Diego and the high is about 88 degrees. If I drain the pool and re-fill it, am I at a pretty high risk of damaging the plaster? Even if I rent a pump and drain quickly, it will still take about 36 hours to refill.

I read in one of the other threads something about "draining from bottom and adding water to top". ?????????

Any advice from you wonderful pros would be greatly appreciated.

 

[JasonLion]

You can drain and fill at the same time. It will require more water to get the levels down an appropriate amount that way, but typically not too much extra water.

Generally you want to fill on the bottom and drain from the top. Fill water is typically colder and will sink to the bottom. If your fill water is warmer than the pool you do it the other way around. If you do this while the main pump is either off or draining to waste, the amount of mixing that goes on in the pool will be minimized and you will use less extra water.

Fighting algae when CYA is around 200 is fairly hopeless. I recommend waiting on adding more chlorine until you get your CYA level down to something more reasonable.

 

[mrs milty]

Thanks for the quick response.

Do you know how long the plaster can be exposed before it starts getting damaged? My pool is 16 years old and (in my non-expert opinion),
the plaster is not in that good of shape to start with. The temps do start cooling down around 5pm and the pool is shaded by about 4pm. If we started draining with a fast pump and refilling that evening, it would leave part of the pool exposed the following day. Is this amount of time trouble in regards to plaster?

I'm not sure how much temperature difference there is between our fill water and pool water. I'll investigate that. Water out of the hose is pretty warm this time of the year.

Thanks again!!!

 

[Bart]

Just out of curiosity, how does the CYA get up that high?

I was under the impression that low CYA was the common problem

 

[mrs milty]

Honestly, I am not sure, but here is my best guess:

We have used Pool Time 6-in-1 shock and chlorine tablets for 10 years. Both have stabilizers in them. When my algae problem came along, I added a couple bags of the shock, and added a couple more bags a few days later. I did accidentally add 1 cup of stabilizer (thinking it was ph up), but that is the only time I have ever purchased or added stabilizer. I haven't ever drained my water, and I've lived here for 10 years. Water is pretty scarce in this part of the country.

If that doesn't explain it, then I'll just say "It's all my husband's fault".