Got My Test Kit - Thoughts On My Results?

[sws1]

Got my TF100 test kit today and immediately ran out to test.

25,000 gal inground, vinyl lined pool

Live in NJ. Pool gets direct sun from morning until 4pm. Then shade.

Trichlor pucks in auto-chlorinator. (4 or so per week)

Cal-Hypo (2 lbs) shock per week.

Algaecide and clarifier (4oz per week)

(This is the approach from pool people who maintained for first half of summer.)

The pool has also been super clear all summer. No chlorine smell. All great.

Here are my results:

FC: 13

CC: 0

TC: 13

pH: 7.5

T/A: 130

CH: 400-500 (Had to do test twice because I gave up when didnt' turn blue. Maybe it's a hair lower.)

CYA: Best guess is 120-130, given than it's above the 100 line by a little bit. Didn't have time to dilute by 2.

SO - Clearly have very high CYA and CH due to the use of chlorine sources. I've been starting to backwash every week now to flush a few inches of water. This'll take a while, but it's more manageable. Not sure if I'm simply offsetting what I'm putting in, or if I'm gaining ground on the CYA / CH issue. NJ has been very dry this year, so there's been minimal rain.

If I wanted to switch to liquid chlorine for the rest of the summer (5 more weeks), about how much chlorine, and how often? And would I need to shock weekly?

[dscriterium]

Newbie,

The trichlor pucks have driven your CYA too high.

Likewise, the Cal-hypo shock has driven your Calcium pretty high also....manageable, though.

I know you knew that already but I am simply confirming it.

Tell me the size of your pool and I'll give you some help on figuring how much liquid chlorine you'll need.

[sws1]

Newbie,

The trichlor pucks have driven your CYA too high.

Likewise, the Cal-hypo shock has driven your Calcium pretty high also....manageable, though.

I know you knew that already but I am simply confirming it.

Tell me the size of your pool and I'll give you some help on figuring how much liquid chlorine you'll need.

My pool is 25,000 gallons. (20x40. 3' shallow + 5.5' deep)

When I get to draining some water out, is it better to do it just before the closing, when the water is clearer, or do it after opening when the water is green and gross? Seems a bit like a waste to do it in the fall if I'm just gonna close it up, but I can't imagine dumping green water out into the street is a good thing.

[dscriterium]

For that pool and that CYA, a samll jug of Clorox put into the pool each day should be just about right. In fact, you should not have to shock if you will put that much in Daily. If your FC decreases over the next few days, increase the dosage just a little. If FC increase over the next few days, cut back a little on the Clorox.

I would dump the water in the Spring. Dumping algae into the street is perfectly harmless. Dumping it into your yard is probably better. Lot's of nutrients.

[PaulR]

I'd agree with dscriterium. If you maintain your FC where it is, with bleach, you should not have to shock. Also, assume that next spring you will dump and replace at least 1/2 your water. If you do a CYA test with a diluted sample, that will give you a better idea how much water to replace. Check with your local water dept, some jurisdictions require that you drain into the sewer (not the street or your yard); my area has rules like that.

Regarding CH, the level you report is manageable as long as you keep pH in the 7.2-7.5 range, no higher. When you turn off the trichlor, you will probably start seeing the pH go up, because of the high TA. (The trichlor is acidic and has been helping manage the pH for you. When you stop using trichlor you will need to start adding acid to control the pH.)

The good news is, your drain/refill in the spring will also lower CH some; how much depends on the CH in your tap water.

--paulr

[sws1]

I'd agree with dscriterium. If you maintain your FC where it is, with bleach, you should not have to shock. Also, assume that next spring you will dump and replace at least 1/2 your water. If you do a CYA test with a diluted sample, that will give you a better idea how much water to replace. Check with your local water dept, some jurisdictions require that you drain into the sewer (not the street or your yard); my area has rules like that.

Regarding CH, the level you report is manageable as long as you keep pH in the 7.2-7.5 range, no higher. When you turn off the trichlor, you will probably start seeing the pH go up, because of the high TA. (The trichlor is acidic and has been helping manage the pH for you. When you stop using trichlor you will need to start adding acid to control the pH.)

The good news is, your drain/refill in the spring will also lower CH some; how much depends on the CH in your tap water.

--paulr

Thanks. If I switch to liquid chlorine now (to prevent even higher CYA), do I need to add it every day since I'm no longer using an automated chlorinator. Presumably I have to.

What sucks is that I have to use the more complicated chlorine test in my test kit rather than a strip since my FC is so high. And a FC of 12 means ALOT of drops to do the test.

[chem geek]

You can use the 10 ml sample size where each drop is 0.5 ppm or can even use a 5 ml sample size where each drop is 1 ppm which will save you drops since you are only looking for an approximate FC level.