New User Getting Butt Kicked By Algae

[TCP007]

Hello: I live in SW Michigan and have a rectangular, gunite pool. It is 36' x 18' and holds approximately 30,000 gallons. I have lived here and wrestled with this pool for 8 years. This year has been a real head-scratcher for me, but I guess I've just always had good luck. I believe I have mustard algae that keeps coming back within a week or so of eradication (or so I thought). I have been using AquaCheck 6 panel strips, but I am going to order a Taylor test kit via the links provided here. My CYA is low (0 or below) and PH high (8.4 range). TH, TC, FC all appear to be good. TA had been a bit high. I added 2 gallons of HCL last week and it helped. PH appears to be between 7.2 and 7.8, but CYA is still low (somewhere between 0 and 30, but closer to 0). TA came down closer to 180. I am vacuuming all visible algae to waste right now (pool level coming back up now) and will brush walls. I picked-up another 2 gallons of HCL and 10 gallons of liquid chlorine. I have more reading to do on your site, so not quite sure how many gallons of Chlorine I'll dump in. I'll add 1 gal of HCL and wait to test, but I'm guessing I'll end up adding both gals. It appears that my chlorine isn't working effectively with my CYA so low. Sorry for this yawn-inducing post, but... this is why I have joined. It didn't take me long to realize the moderators here know what they're doing. I appreciate reading and learning from all the experienced pool lovers here.

[TCP007]

Update: I ran out of daylight vacuuming to waste, so did not shock. I did add both gallons of HCL, and as of this morning I only noticed a slight improvement in the CYA. I did notice that it appeared to bring down both TC and FC readings. I plan to finish vacuuming visible algae after work. I think I should add another gallon of HCL (?) before adding the the liquid chlorine.

Test kit has been ordered and appears to be on schedule for a 8/7/14 delivery. Sorry I don't have better info at this time.

I failed to mention that the pool utilizes a sand filter (not sure what brand, but it's black with a multi-function selector on top), a 2-hp Hayward Super Pump. I replaced the sand 4 or 5 years ago. Solar blanket provides more than enough warmth. Unfortunately, this pool gets sunshine almost the entire day. I am currently removing the blanket at night to let some heat out. Current temp and humidity isn't helping much.

[Watermom]

Kinda hard to know how to help without some good numbers. Hopefully your kit will arrive tomorrow.

HCL is ??? and why are you adding it?

Welcome to the Pool Forum!

[TCP007]

HCL is Muriatic Acid or Hydrochloric Acid. I'm adding in order to raise my CYA level and also bring my PH and TA down.

I decided not to wait another day for the kit (and hope it actually arrives as estimated), so I added another gallon of Muriatic Acid and later shocked with 10 gallons of liquid chlorine. Hoping for better results with the extra gallons of chlorine.

I will definitely provide better readings when the Taylor test kit arrives. Thank you!

[Watermom]

HCL or muriatic acid will not raise CYA. You need cyanuric (or isocyanuric) acid.

[BigDave]

@Watermom: HCl is hydrochloric acid, it's the same as muriatic acid. I think it's being used to lower TA.

@TCP007: Don't let the pH drop below 7, it can damage your pool. If you are trying to reduce TA, you'll need to aerate the pool to bring pH up after adding HCl.
If this were my pool, I would concentrate on killing and removing the algae before trying to adjust TA, 180 is high but livable. The test stips are useless for CYA but if you see alge, you need more bleach. Hopefully the K-2006 arrives today and you can get a good measure of CYA level.

[Watermom]

For some reason I didn't think muriatic and HCl where the same exact thing which is why I questioned it. But, I did a little research and found out they were. Thanks, Dave. But, he also states that he is using it to raise CYA which I addressed in my post above yours.

[BigDave]

@Watermom: Ah! I didn't see that post before responding, thanks.

@TCP007: I stand behind my advice in post #6 and Watermom is right, HCl won't raise CYA.