Edit: the final version of these instructions can be found in Pool School as Beginners Guide for Seasonal/Temporary Pools. End-edit
Caution: These are experimental suggestions. They need to be fleshed out and tried in the real world. Feedback welcome, ESPECIALLY FROM INTEX OWNERS.
Very small above-ground pools will benefit from somewhat different handling compared to "regular" pools. Examples of these very small pools include most of the Intex Easy Set pools, and the smaller Intex Metal Frame pools. Where the dividing line between "very small" and "regular" should go is not clear; maybe around 5000 gallons.
My thoughts about how to manage the water chemistry of these pools are based on a few observations.
1) They are tiny.
2) They are vinyl.
3) They are cheap.
4) They are not permanent.
These observations lead me to the following conclusions:
CH: Low CH is irrelevant to vinyl. High CH could be an issue depending on TA and pH. But you'd need really nasty-high CH in the fill water for this to be a problem, and probably requires a lot of evaporation/refill to accumulate to that level; this can be solved by dumping and refilling. Hence: No need to test for CH.
CYA: This seems to come in 4-lb containers. A very small pool might not need more than 1/2 lb. Buying 8 seasons worth of CYA is a waste. Use the dichlor/bleach system originally developed for spas to establish a reasonable CYA level. If you follow the system you don't really need a CYA test.
I think the appropriate recommendations are as follows.
Test Kit: Get a drop-test kit that handles pH, chlorine, and TA. Don't need anything else (sorry duraleigh!).
Startup: Test and fix pH first. Then start the dichlor. I'm estimating the quantity of dichlor needed is 1/2 lb per 1000 gallons, rounded up; I'm pretty sure this should get CYA into the 30-50 range in all cases. For sunny southern climes, this could be increased to 3/4 lb per 1000 gallons, which I think gets you into the 50-70 range (but I didn't check all that carefully). The dichlor dosing looks like 1 oz (volume) per 1000 gallons gets you around 5ppm FC; it would take one to two weeks to use it up. When the dichlor runs out, you will have a reasonable CYA level, and it's time to switch to 6% bleach.
Maintenance: 6% bleach for chlorine; 2 oz per 1000 gallons is 1ppm FC. The target FC would be in the 3-5 range. pH and TA managed as usual, except maybe we should recommend dry acid (not muriatic). I don't like the thought of adding muriatic to something that looks like an Easy Set.
Slings and arrows welcome. Intex owners willing to be guinea pigs ESPECIALLY welcome.
--paulr
Caution: These are experimental suggestions. They need to be fleshed out and tried in the real world. Feedback welcome, ESPECIALLY FROM INTEX OWNERS.
Very small above-ground pools will benefit from somewhat different handling compared to "regular" pools. Examples of these very small pools include most of the Intex Easy Set pools, and the smaller Intex Metal Frame pools. Where the dividing line between "very small" and "regular" should go is not clear; maybe around 5000 gallons.
My thoughts about how to manage the water chemistry of these pools are based on a few observations.
1) They are tiny.
2) They are vinyl.
3) They are cheap.
4) They are not permanent.
These observations lead me to the following conclusions:
CH: Low CH is irrelevant to vinyl. High CH could be an issue depending on TA and pH. But you'd need really nasty-high CH in the fill water for this to be a problem, and probably requires a lot of evaporation/refill to accumulate to that level; this can be solved by dumping and refilling. Hence: No need to test for CH.
CYA: This seems to come in 4-lb containers. A very small pool might not need more than 1/2 lb. Buying 8 seasons worth of CYA is a waste. Use the dichlor/bleach system originally developed for spas to establish a reasonable CYA level. If you follow the system you don't really need a CYA test.
I think the appropriate recommendations are as follows.
Test Kit: Get a drop-test kit that handles pH, chlorine, and TA. Don't need anything else (sorry duraleigh!).
Startup: Test and fix pH first. Then start the dichlor. I'm estimating the quantity of dichlor needed is 1/2 lb per 1000 gallons, rounded up; I'm pretty sure this should get CYA into the 30-50 range in all cases. For sunny southern climes, this could be increased to 3/4 lb per 1000 gallons, which I think gets you into the 50-70 range (but I didn't check all that carefully). The dichlor dosing looks like 1 oz (volume) per 1000 gallons gets you around 5ppm FC; it would take one to two weeks to use it up. When the dichlor runs out, you will have a reasonable CYA level, and it's time to switch to 6% bleach.
Maintenance: 6% bleach for chlorine; 2 oz per 1000 gallons is 1ppm FC. The target FC would be in the 3-5 range. pH and TA managed as usual, except maybe we should recommend dry acid (not muriatic). I don't like the thought of adding muriatic to something that looks like an Easy Set.
Slings and arrows welcome. Intex owners willing to be guinea pigs ESPECIALLY welcome.
--paulr