GEting pool chemistry balanced

[fishface]

Hello...newbie here, and first time pool owner, came with house and has unknown history, the the previous owners left a tub of 1 inch chlorine tablets, which I continued to use in the floater.

The good - the pool doesn't smell bad in any way, water is clear and no algae,

I'm not sure if I'm having trouble or not, I've been using Aquacheck Select 7-Way Test Strips, and I got very very high CYA readings, more or less of the scale, so I read a bit about that, and then drained off around half of the pool water, tested over several days and the CYA has gone down, but still isn't great. The problem is that when I add chlorine (using the 1" tabs) the FC and TC seem to go up together in step, is this normal?

I have shocked, double shocked, (I'm aware this now adds to the CYA), and it still happens, and the strips is seem to indicate that my pH was getting lower, so (see 7/11/12 below) so I added about a box of 20 mules and this has raised the pH a little and the TA, and my TC/FC and at the high end now, but still within the "OK" on the test strips.

I now want to work towards using household bleach, liquid chlorine approach which many of you recommend on here, how balanced do I have to get my current chemistry before making the switch? Do I have to drain the pool?

Pool temp is usually between 81-83F.
Date Hardness TC FC pH Total Alkalinity Cyanuric Acid

Before 50% pool drain 300-500 0.5 0.5 7.2 80 300
7/1/2013 300-500 0.5 0.5 7.2 80 100-150
7/2/2013 300-500 0.5 0.5 7.2 80 100-150
shock 7/3/2013 300-500 2 1 7.3 80 100-150
7/4/2013 300-500 1 1 7.2-7.8 80 100-150
7/5/2013 (added more tablets) 300-500 1 3 7.2-7.8 80 100-150
7/6/2013 (added more tablets) 300-500 1 3 7.2-7.8 80 100-150
7/7/2013 300-500 3 3 6.8 80 100-150
7/8/2013 shocked 300-500 5 5 6.8 80 100-150
7/9/2013 300-500 5 5 6.8 80 100-150
7/10/2013 300-500 5 5 6.8 80 100-150
7/11/2013 after double shocked 300-500 5 5 7 100 100-150 (also added 3/4box of 20 mules)

 

[Smykowski]

TC=FC+CC, so if you add Free Chlorine, by definition Total Chlorine will go up as well.

In terms of making the switch, all you have to do is commit. Then you need to buy a good test kit, because maintaining the pool our way is impossible with strips or pool store testing.

Given your struggles, I would then suggest SLAMing the pool. Read about it in Pool School, and ask us any questions that come up.

Welcome to TFP!

 

[Isaac-1]

My first suggestion is to get one of the suggested test kits and stop using trichlor tablets. Test strips are bound to lead to confusion, frustration, and wasted money on chemicals one way or another.

Ike

p.s. I assume you have already read the pool school link in the upper right, but if not read it

 

[fishface]

Thanks both.

I'll order the K2006 test kit tonight, do some reading up on this forum, and then I'll report back.

 

[linen]

Welcome to tfp, fishface

I agree with Smy and Isaac, you are flying blind with those strips. I doubt this is the case, since apparently a lot of cya has been put in the pool, but wouldn't it stink if they were wrong about the cya level (they often are) and you really didn't need to do any drain/refill. Here is the link to the pool school article on test kits: http://www.troublefreepool.com/pool-school/pool_test_kit_comparison Many of us have the tf-100 since it really is the best value and Dave (username duraleigh) has very fast shipping.

 

[JohnN]

[EDIT] I see you are going to order the test kit, so you can ignore that part[/EDIT]
pH is going down because the tablets and "shock" are acidic, and quickly lower the pH. You should get the TF-100 or K-2006 which is linked to in my signature. When you get it, do the CYA test with 50% pool water and 50% tap water and double the result, so you can get a better idea of where your CYA is at. If it really is in the 100-150 range, you will want to do a partial drain to lower it. It is possible to maintain a pool with high CYA, but if you let anything slip, you will be using a LOT of bleach to clear it up.