Now that our new pump is installed, it is time to get our water chemistry under control. The water is a nice shade of green, I can see the Polaris on the bottom of the shallow end but not the drain in the deep end. Mrs. Sprocket sorted out her new TF 100 kit and got the following results:

FC 7ppm
CC 0
TC 7ppm
pH 7.8
TA 110
CH 450
CYA 60

We looked at the pool calculator, but I'm not sure if we are interpreting it correctly.

I cant tell if you have a salt water pool or not? If not I would say your CYA is on the high end for a non salt water pool.

From the sounds of it, it sounds like you need to shock.

pool-school/shocking_your_pool

To get your shock value use this table

pool-school/chlorine_cya_chart_shock

If non salt water your shock level is 24, if salt water your shock level is 24 as well.

So what I would do is put in enough bleach to bring your level from current 7 to 24.

The pool calculator is pretty easy to use

I assume you already have the link if not here it is http://www.poolcalculator.com/

At the top where it says size put in your gallon size of 21,000. For each test you will see two boxes next to each other labeled at the top Now and Target. The now box is for your current result and your Target is what you are trying to get to. So what I would do is in the now filed in the FC section put 7 and target 24 and that will tell you how much bleach to put in. Make sure when you get it, that it is 6%. Before you add the bleach adjust your pH down to around 7.2. That will require 57 fluid ounces of 31.45% muriatic acid. Once you get this down and after about 30 minutes of adding that, I would then do your bleach. Dont worry about anything else, because bleach is what is going to kill that algae that it sounds like you have. So after 30 minutes of adding the acid then add the bleach. This will make sure you get your pH down a little, because any value for FC over 10 pH will be wrong. So you will want to try to test as often as possible and keep the FC at shock level of 24. The longer it sits below that the longer it will take to clear. Pending how bad it is, after 3-5 days you should start to see some clearing of the water shade starting to get more blue.

When it appears to start looking more blue instead of green then you will want to do the OCLT-Overnight Chlorine Loss Test

pool-school/overnight_fc_test

So hopefully that can get you started some.

What questions did you have about the pool calculator?

What threw me off on the pool calculator was that for CYA it suggested draining 1/3 of the water.

I'm headed to Walmart for bleach. We can get 12% at the pool store, but it's not as convenient.

Regarding acid, I've always "eyeballed it". How do you measure it?

Mr. Sprocket,

60 CYA is at the higher end for a manually chlorinated pool as yours is but I think I would leave it alone this close to the end of the season.

If you have successfully "eyeballed" your pH reduction before, you can do so again by probably adding about a quart which should get you into the mid 7's. While "eyeballing" is not what we encourage, you seem to have moved your pH before by doing so.

Once your pH is lowered, then as mnp suggests, shock your pool. However, please read "How to Shock your pool" in Pool School before you start. You will find it is a lengthy process rather than a one time dose and it will consume more bleach than you expect. The results you get will be a crystal clear pool.

Read the "Shock" article, follow it precisely, and get some extra clorox.....you'll be on your way!

Thanks guys. I just finished fixing (hopefully!) the leak at the outflow of the pump. I did install a union just in case I need to take it apart again.

From what I have read, the only difference between pool store chlorine and bleach is 12% vs. 6%.

For the cya If your target number is lower than the now number if will tell you to do a partial drain and refill. If your cya level is 60 just enter 60 for now and target and it won't tell you to drain.

Keep in mind that I am in FL so we don't actually "close" the pool.

Put your city and state in your sig so everyone knows that. Even though you don't close, I would still leave the CYA alone. It will come down a little through splashout and it is right at the top end of "just about right" anyway.

We are heading into our dry season and it is still in the upper 80's/low 90's so I'm still losing to evaporation. I had my wife read the pool school section on the shocking process. This morning I added the acid and will add the bleach shortly.

Any question along the way just ask and you will get all the help you need.

OK - my wife just tested the pool again. I'm concerned that the time of day, position of the sun, etc. may be affecting her analysis of the results as she wrote down what I consider unexpected results. Is it possible for CYA to increase by 10 and pH to go from 7.8 to 8.2 after I added the necessary muriatic acid this morning? I was glad(I think) to see FC only dropped by 3ppm. We already updated the pool calculator to determine how much liquid chlorine and acid to add based on these results.

This evening's results:

FC 21ppm
CC 0
TC 22ppm
pH 8.2
TA 110
CH 450
CYA 70

I SHOULD ALSO MENTION THAT I USE A FLOATER WITH 2 3" PUCKS OF AQUA CHEM TABS PLUS. WOULD THIS BE WHY MY CYA IS HIGH?

Remove them and do not reuse them. They will only continue to add unwanted (in your case) CYA.

You cannot accurately test for pH in the presence of high chlorine. You will get a false high reading. Disregard pH testing until your shock process is complete.

I read that in Pool School after posting. My hope was to delegate this to my wife but.......

The pool is looking a lot better this morning. Pump running 24/7 brushed last night and this morning.

FC was 21 when I got home from work and I added necessary PS liquid chlorine per pool calculator. I accidentally added a litle too much because late last night FC was 28. This morning it was 27.

Pool is really looking a lot better this morning. FC was 24 last night and 21 this morning so added more PS chlorine. The tint of the water is now blue, although still cloudy. I can easily see the bottom drain. Pump is running 24/7 and I am brushing at night and in the morning. I plan to clean the cartridge tonight, but I did not note the pressure when I started the shock process.

One note - I ran the polaris this morning and it is on steroids compared to the old hardware. The new pump must be pulling a lot more water from the pool than the old one.

If it is so fast that it doesn't pick up well you may have to recalibrate the speed again.

There's not much **** on the pool bottom to tell, but the sweep sure needs adjustment! It nailed me twice this morning.

Pool looks great this morning. Very clear, passed OCLT last night and CC is zero.

I assume the next step is to allow the FC to drift down to 7 based on our CYA of 60 over the next few days before testing pH, TA, etc. We have had a fair amount of evaporation th past few days due to 90 degrees and no rain so I need ot add some water.

If you can post some pictures of it. If your lost less than 1 FC, CC is less than .5 and water is clear then all is well. For me to make sure I have always, even after passing an OCLT, I would still try to keep pool at shock level for one more day and pass the OCLT to make sure. To me if it passes the OCLT two days in a row that takes out any hint that there may have been some slight test error on my part. Just a little backup for me, but not necessary from what the site says. I would rather do it right the first time instead of doing it again.