Tri-Chlor Pool Tablets & Pool Shock

by Raelene

I am using Tri-chlor tabs in my pool, but the chlorine levels are low constantly. The pool shop testing the water has had me shock the water twice in the last weeks along with adding other chemicals.

We now have algae and were told to add acid and a clarifier. It has helped some but is still very cloudy. I have only had the pool for several weeks.

What should I do?

Good question

It's good that you're using Tri-chlor tabs to raise the cyanuric acid (CYA) in your pool. The reason that you can't keep the chlorine level up between 1.5 - 3.5ppm is your CYA is either too low or too high. It should be between 20 - 40ppm.

Chlorine Tablets

Too low means you need to get that level up. Too high means you probably need to do a partial water change, 1/3 - 1/2, then test your CYA again. When you shock the pool you need to be sure you're getting to the "Super-Chlorination" level which is at least 10ppm above your chlorine level. Obviously if your pool is green then it's safe to assume there's no chlorine available. Try to shoot a little over, maybe 12ppm.

Adjust Your Swimming Pool Chlorine

If you don't reach this level it will be harder to kill the algae and you'll end up using more and more chlorine to combat the issue. Also watch yourself when your adding "other chemicals". When you have a green pool the best way to clear it up is to use a good dose of chlorine. When everything is in line you'll find you'll be using less and less of the "other chemicals". Adding acid will drop the pH and alkalinity. Be sure you're using it properly.

Muriatic Acid..Swimming Pool Chemistry

Metals in the water, copper and iron, can sometimes turn a pool green after a shock. Take a sample of your water to your pool store and have them test it for metals. When you have an algae issue the best way is to first scoop out any debris from the pool, brush the sides, steps, and floor. Be sure your filter is clean and working properly and, with sand filter and DE, backwash once per day. Cartridge filters need to be cleaned manually. This link will give you the best starting point to clear up your green pool water:

Remove Swimming Pool Algae

Be sure your chemicals are in line for a good shock:

pH 7.0 -7.2

Alkalinity 80 - 100ppm

Hardness 150 - 250ppm (mainly for plaster pools)
Pool Tips

I would encourage you to have a good Taylor Reagent K-2005 or 2006 test kit. It takes a little getting used to but it's worth it.

Water Testing Kit

Algaecides are only good for preventative measures, not for clearing up a pool. Only chlorine can do that.

Pool Algaecide

There are a million reasons why your pool can be cloudy. With your issue it is probably algae. Do the above and look at this link:

Cloudy Pool Water

It will take time to clear up your pool. Remember to keep filtering, backwashing, and keep your water level correct. Too high or low and and skimmer can't do its job.


Click here to post comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Chlorine Tablets.

Do I Need Chlorine Tabs Even If I Have A Salt Water Pool?

by Effie

We have a salt water system put in. My pool maintenance person still add chlorine tablets to our skimmer once in a while.

Is that necessary because I thought converting to a salt converter means we do not use chlorine tablets anymore. It still burns our eyes.

Thanks for the question Effie

First you need to tell the pool person to stop putting chlorine tabs in the skimmer and get a tab floater. When the pump turns off the tabs keep dissolving. Then the pump turns back on the system gets a huge blast of acidic water. It can ruin the gaskets and seals pretty quickly. A tab floater is around $10.

There are tabs that allegedly stop dissolving when the pump turns off so it's safe to put in a skimmer, but better safe than sorry.

You do need stabilizer (cyanuric acid/CYA) when you have an outdoor pool but the question is do you need tabs if you have a salt pool? My opinion is you should have at least 30ppm of CYA in the pool and then you can allow the chlorine cell to do it's job through the week.
Having a constant stream of CYA while having a salt pool may not be needed.

Chlorine Tablets

Pool Chlorine Tablets

A salt pool is not a chlorine free pool. You probably have a salt cell that produces chlorine for you. All this means is that you don't need to manually add chlorine to the pool, but the salt water generator still produces hypochlorous acid, which is chlorine.

Salt Water Swimming Pools

Chlorine Generator

For every 10ppm of chlorine added with Trichlor tabs you'll raise the CYA by 6ppm so tell the maintenance person to test the CYA. Keep it between 30 - 50ppm and the chlorine between 1.5 - 3.5ppm. The only way to reduce CYA is to do a partial drain and refill.

Burning eyes could be the result of an improperly balanced pool. If you could get me your chemical readings I can look them over and let you know if there's anything that needs to be adjusted. Take a sample of pool water to your local pool store for analysis then email me the results.

Chlorine, CYA (cyanuric acid/stabilizer), pH, Alkalinity, Calcium Hardness, and Metals (iron and copper).

Hope this helps and have a great rest of the Summer.


Click here to post comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Chlorine Tablets.

Above Ground Pool, 30,000 Litres Has What I Am Told Chlorine Block

by Allan
(South Australia)

I was told to massively dose the pool with 5-6 times the dose of chlorine. It appeared to work 2 weeks ago when it first started but now has returned.

My pH is very low and my chlorine level is very high. Is massive dosing the thing to do and if so why has it returned?

Thanks for the question Allan

Here's what chlorine block is... An answer given to a pool owner when the pool store employee doesn't know what he's talking about. There's no such thing as chlorine block.

I'd like to have a complete list of your chemical readings. Chlorine, pH, alkalinity, hardness, and CYA. This will tell me what's going on with the pool.

If the pool is having a problem holding the chlorine it could be an issue with the CYA but I need the readings to determine this.


Click here to post comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Chlorine Tablets.

Tying Off Pool Tablets

by Valerie Long

We are going away for 3mths in winter, so have had a pool blanket installed. Have purchased Tablets for the 1st time. Usually use granulated chlorine. As we have the pool cover my son needs to be able to fill the dispenser without having to move the cover.

Is it alright to tie a string from the dispenser to a rock near the side of the pool so it doesn't float around the pool, but stays mostly in the same place. It is a large pool 11metres by 6metres.

Thanks for the question Valerie

Yes it's alright to tie off a tablet dispenser. However, you need to be sure someone is checking the chemicals on a weekly basis.

I know you're going into Winter down there but the water still needs to be checked and the filter backwashed if you have a DE or sand filter. Weekly pool maintenance still needs to be performed. The tabs will probably dissolve within 3 months and if chlorine is not being added you may come back to a green pool.

I hope this has answered your question to your satisfaction.

To post a reply, or if you have a similar question, you can see your post on the Q&A page in the "Chlorine" category.

Check back to this post for updates or answers.

If you feel your situation is more complex and want immediate assistance (within 24 hrs) you can make a donation of your choice and I'll answer your questions by phone.

Have I helped you find a solution to your pool problems? Did this information help you? Please consider making a donation to help keep this site going. Thank you.


Click here to read or post comments

Join in and write your own page! It's easy to do. How? Simply click here to return to Chlorine Tablets.

eBooks Are Perfect Desktop & Mobile Device!!

swimming pool care, basic pool care, above ground pool maintenance, inground, salt water

Click Here To Learn How This eBook Can Save You TONS Of Time & Money

Click Here To Learn The Best Way To Clear Up Your Pool 

All Resources In One Convenient Package. Click HERE To Get Started.

Recent Articles

  1. Pool Float & Sweep

    How do I keep the hose from my pool sweep and the floater from colliding? If I tie the float off where is the best place, and one last if the float is tied off.

    Read More

  2. The calcium hydochlorite will not dissolve in our pool

    The calcium hydochlorite will not dissolve in our pool. It is suspended in the water

    Read More

  3. Easy Swimming Pool Care: Maintenance, Instructions, Tips, Guide

    Simple Swimming Pool Care Guide & Pool Water Chemistry

    Read More