Aquachek Pool Water Test Strips..Low Chemical Readings

by John Pollacco
(Malta)

I use Aquacheck sticks to test my pool water.

Today's tests repeatdly gave me the following results: -

pH Low below 6.2ppm, free chlorine high 10; ppm total alkalinity low 0 and ppm stabilizer low 0. I did add acid but did not see any change.

What's wrong?

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Thanks for the question John

I would first ask if there has been any outside and sudden influences that would change the chemical makeup of the water, i.e. heavy rains, windstorms, heavy use of the pool, things of that nature.

If not, then how were the readings before this happened? If you were using the same strips from the same package and were getting pretty consistent results for weeks at a time, then all of a sudden everything is out of sorts, it means either something from the outside influenced the pool, or the test strips went bad for some reason.

If they were left out in the sun, dirt or debris got on them, pool chemical spilled on them, etc... There have been cases where kids would throw laundry or dish detergent in the pool, which would cause the water to foul and bubble up.

For water testing, I would highly recommend a Taylor FAS-DPD K-2006 water testing kit. It's the kind I used in Arizona when I maintained pools and the one I use at the YMCA pool.

A little on the expensive side, about $80 or so, but it's worth the investment. You need to get the pH level up to 7.6 - 7.8, chlorine between 1.5 - 3.5ppm, alkalinity 80 - 100ppm, and stabilizer, cyanuric acid (CYA), between 30 - 50ppm.

The K-2006 kit has the tests for all of these chemical readings. You can find how to raise and adjust all of these on my site.

Although the test strips are pretty convenient, I've found the FAS-DPD kit is the most accurate. It does take a little getting used to, but it's worth the time. Get the kit, then compare it with the strips you have. If they are not equal, then the strips probably went bad.

The pool chlorine cannot get that high without adding chlorine. Pool chlorine will always go down, not up, unless someone is adding it. Hope this helps and let me know how this turns out for you

Robert

Low Levels of Total & Free Chlorine On Test Strip & Pink pH Salt Water Pool

by N. Yawney
(Florida)

My salt pool test strip..total hardness..250..
Total chlorine... 0
Free chlorine...0
Ph bright pink..maybe 8.4 or higher
Total alkalinity...120
Stabilizer...0
Copper ppm...0.2

We have rain every day in Florida right now. Cover has been off. I have the Krystal Clear saltwater system model cs8110. We have had only about 2 hours swim time and only 2 people in pool.

Set up pool 2 weeks ago. Thought I had a salt system for some reason but didn't. I added salt water syarem 4 days ago after an invisible algae cleaning and a pool shock safe for all pools.

Added 135 pounds salt. I have an above ground 18 feet wide by 48 in deep Intex pool with skimmer.

What do I do?

Thanks a million for helping!

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Thanks for the question

First I'll start with your pool size. For 18 x 48 pool, you'll have 7,646 gallons. You use 3 - 5 50 lb. bags of salt to bring the water salinity to 3000 - 4000ppm per 10,000 gallons. The question said 135 lbs. was used. You should be close to the proper range.

You need to check the salinity using a proper salt meter. Never simply go on the salt cell reading. You need to manually check the salinity as compare that reading with the salt cell reading.

Next are your readings. The first thing that jumped out at me is the lack of stabilizer (cyanuric acid/CYA). A normal reading is 30 - 50ppm.

This is critical to get into the pool. If you don't have it the chlorine will be used up very quickly. Shock the pool with Dichlor chlorine. This is a stabilized form of chlorine. Once you reach the 30 - 35ppm mark, stop with Dichlor and go back to regular liquid chlorine.

Be careful when using Dichlor as it can get out of hand quickly. For every 10ppm of chlorine added with Dichlor, you'll raise the CYA by 9ppm. For every 10ppm of chlorine added with Trichlor tabs you'll raise the CYA by 6ppm.

It's 1 1/3 lbs. of Dichlor per 10,000 gallons of water to not only shock a pool, but to raise CYA 10ppm. You want to get the 30 - 35ppm CYA. Use 1 1/2 lbs. of Dichlor broadcast around the perimeter of the pool with the pump on FILTER. Sweep very well and retest after 8 hours. Make another adjustment if needed. Be sure to turn the chlorine cell OFF during the shock process.

The TA is just a bit high but can be lowered using muriatic acid. The acid will also lower the pH. It's 12 oz. of acid per 10,000 gallons to lower the pH 0.2 per 10,000 gallons. I'd use about 1 qrt. broadcast around the perimeter of the pool with the pump on FILTER, sweep very well, then retest the pH and TA after 8 hours. Acid is heavy and sinks to the bottom. If you don't sweep the acid may bleach out the liner.

You can save a little time. Shock the pool with Dichlor and add the acid after 2 - 3 hours. NEVER do one application on top of another. Always allow for 2 - 3 hours between applications.

You need to do these things because it seems you're on the verge of a bad algae bloom. If you do have algae right now, it's important to shock the pool.

Shocking is a process, not an event. The trick is to get AND keep the chlorine above 10 - 12ppm for a period of time. You'll need to manually dose the pool with chlorine to keep it at 10 - 12ppm. Make the adjustment at night, sweep very well, then retest in the morning. Be sure to have the pump running 24/7 and backwash once per day. You can go up to 15ppm, but no higher. Anything after that and you're wasting money and chemicals.

If you're getting heavy rains, the extra water is going to dilute what you've done. There's simply no way around this. Be prepared to keep making adjustments while the rain is around.

Hope this helps.

Robert