Aeration / Acid Treatment to lower Alk

Not sure if I have the answer to my question below, but I have successfully accomplished the Aeration / Acid treatment as suggested in the forum taking my TA from 260 to 110 in about 5 days using about a gallon of Muriatic Acid. I did so at pH hovering at 7.5 to 7.7 which is above the suggested. Not that I wouldn't have tried the lower pH but it wouldn't drop once I started the Aeration adding about 20 oz of Acid every 12 hours.

Before I started I was having a problem keeping the pH up and having high TA but now I may have to cut back on Aeration. I do have a question as to why my procedure worked so well with the higher pH? I think it may have to with the higher altitude. Albuquerque is at about 6000 feet where I am against the mountains. Anyone know better about the science of the altitude effect on this procedure?

Unlike another writer to the forum, 2 year old Muriatic Acid worked just fine.

Fiberglass Pool - 7500 gallons - 10 x 25 x 4 ft
FC: 1-3
CC: Not detected
ph: 7.5 - 7.7
CYA: 100
TA: 260 down to 110
CaHardness: 200

I am looking to drop the CYA and raise the Chlorine. Pool level is currently down 3 inches from evaporation for cleaning of the water line. I figure I will need to drain some water before I refill. I have already removed the chlorine tablet floater. I am getting some liquid Chlorine tomorrow to raise the chlorine to a solid 3-4 or may use some Calcium Hydro if the TA drops as I have stopped adding Acid.

Any other tips are appreciated.

Hi, and welcome to the forum!!

Your CYA is not going to drop from evaporation in the water, but if you drain some water before refilling, you might lower it some. You do need to get some chlorine in the pool quickly though--it's amazing how quickly a perfect pool can turn green without enough chlorine. With your CYA at 100, a chlorine level of 3-4 is not going to be enough--for that CYA level, you need to maintain a MINIMUM of 8 ppm at all times, max 15 ppm. You can check out the "best guess chlorine chart" link in my sig for chlorine levels that correspond with CYA levels.

How high is the TA in your fill water? If it's higher than the 110, once you refill, you may have to repeat some of your TA work to get it back down. Part of the reason that you had trouble keeping the pH up before was probably the trichlor feeder--the trichlor is very acidic and will drive your pH down. Now that you've removed it, it makes sense that your pH is staying a bit higher.

Janet

I can't answer your question about if the altitude affects the procedure or not.

But, I can tell you that your FC is WAY too low for a pool with a CYA of 100 and is a big invitation to algae. Plus, the fact that the CYA test cannot differentiate past 100 means that it could actually be much higher than that. Take a look at the Best Guess chart in my signature below.

You have two options:

1. Do a partial drain and refill and try and lower the CYA to a more manageable level. Do NOT totally drain a pool however.

OR

2. Run higher than normal chlorine levels to compensate for the high CYA. (Again, see the Best Guess chart.)

Either way works. Just a decision you need to make. If you do nothing and continue to have chlorine between 1-3, you WILL get algae though.

I'm assuming from the way you reported your testing results in ranges that you are using test strips. Is that correct? We don't feel that test strips are too reliable or accurate. You really need a good test kit. The one we recommend is the Taylor K-2006 or 2006C (same kit, larger bottle of some reagents). If you buy it through the Amazon link in my signature, the Pool Forum makes a little money on the sale which helps us keep this form online. Only buy if the seller is Amato Industries, however. Some other sellers are substituting the K-2005 which you do NOT want.

If you decide to go with option #2 above, you MUST have this kit. Other kits cannot test high cl levels like you would need to run. But, even if you go with option #1, it would still be a good idea to buy it. We like everyone to be able to test their own water with good results. It makes pool maintenance so much easier.

Welcome to the forum, BTW. Hope you enjoy it and find it helpful to you!

EDIT -- Looks like Jan posted while I was typing. Advice is pretty much the same. BTW -- I'm going to ask Ben to take a look at your question about if altitude affects the aeration process and get his take on it.

Quote:

---

Originally Posted by Donski

I am looking to drop the CYA and raise the Chlorine. Pool level is currently down 3 inches from evaporation for cleaning of the water line. I figure I will need to drain some water before I refill. I have already removed the chlorine tablet floater. I am getting some liquid Chlorine tomorrow to raise the chlorine to a solid 3-4 or may use some Calcium Hydro if the TA drops as I have stopped adding Acid.

Any other tips are appreciated.

---

Calcium Hydro? Do you mean Calcium Hypochlorite? I don't know if you're linking Calcium Hypochlorite and TA but I'm pretty sure that Calcium doesn't affect TA. If you already have some Calhypo, it's alright to use as a Chlorine source. I wouldn't go out and buy it. You already have a CH of 200. A little more probably won't hurt if your fill water is good but there's no need for it in a fiberglass or vinyl pool.

After further reading it looks like some Calcium is recommended for fiberglass pools to protect the gel coat and keep cobalt from leeching from the gel coat.

Quote:

---

Originally Posted by Donski

I do have a question as to why my procedure worked so well with the higher pH? I think it may have to with the higher altitude. Albuquerque is at about 6000 feet where I am against the mountains. Anyone know better about the science of the altitude effect on this procedure?

---

Yep, with less vapor pressure on the water surface CO2 will outgas faster.

Yes I mean Calcium Hypochlorite.
I had a range on the Chlorine because it was over several days and the chlorine was changing. We have Leslies Pools here in town and I have been using a dropper kit from them. A good part of the chlorine changes was due to tablets which I have already removed. I wasn't adding to the chlorine while I was mixing in Muriatic Acid. I mixed in another lb of CalcHypo last night to wake up this morning to a level of 2. Today the pool has been at 80 degrees and the cover was off. Also I did a lot of cleaning of the water line with 'Descale-It' which has clouded the water a little. Tonight the level of chlorine is undetectable and I double checked it with a strip. I have added another lb of Calc Hypo tonight. The store doesn't stock liquid chlorine and lithium hypoclorite was coming from another store.

What might be some of my problems I have found is a buildup on the pool walls. As I scrubbed the water line, I find the pool is blue and not white. I only bought the house last year and it already was this way. The white covers the entire inside of the pool under water. I am not sure what to do about it. I am assuming it is from years of high Alk. Last year when I went to the pool store, they said the high alk was natural for this area and not to worry about it. Now I have this problem. Will a lower Alk help remove it very slowly? Is this what is called scaling? I have spent hours scrubbing and only manage to clear off a small area. How do you rid an entire pool of white walls? Right now I am trying to get rid of a dark waterline.

I read on another forum topic or on the Internet the Calcium Hypo can affect the TA by raising it and with my Calcium in range, I didn't want to add to it too much. I'll keep an eye on the calcium level to use up the CalcHypo I have. I believe standard bleach from the grocery store can be used. Can you provide insight as to what to by and how to use it?

I understand the CYA won't go down by evaporation but I figure it is concentrated because of the lower water level. I didn't realize the 100 might be a max reading for the test kit. I have AquaCheck test strips for CYA which goes to 200 but they show 100 the same as the pool store.

Scrape some scale off the side and collect. Put in a glass or bowl--pour some vinegar on it--if it's calcium it should bubble and/or fizz.

You need to get a good test kit.

http://poolsolutions.com/testkit-order-links.html

Some scrapings in a bowl with a few drops of vinegar and there was no bubbling or fizzing.