My pool store is a better deal

[CarlD]

Hi DD.
I go through the exercise you're going through all the time. Generally, I end up using a particular store's 5 gallon carboys of %12 LC because they turn over SO much that it's always new and tests at %14. A little bit of simple math and it's clear it's cheapest to buy that way. It's about $18 for the carboy (I paid the deposit on the 3 I have years and years ago). That's the equivalent of 10 gallons of %7 for $1.80/gallon. Hard price to beat!

Basically the idea for testing LC is to simulate a pool. So I use 10 liters of tap water in a bucket. 2-liter soda bottles are ideal for measuring.
Test the tap water for FC and CC. If it's more than 0, you'll subtract that.
Add 1 milliliter of the LC you are testing to the 10 liters. I use a marked glass eyedropper available at any chain drug store.
Mix and wait a few minutes.
Test the water as you would test a pool and the FC level approximates the % strength of the LC you're testing.

Simple!

[dansdad]

Carl where would a person get a 5 gallon jug and what do you do fill a gallon jug from the 5 gallon carboy or what? Thanks Dave

[dansdad]

Carl I can buy an empty carboy its where to fill it

[CarlD]

DD: Usually, if a pool store sells them, then they sell FULL carboys (they are blue) and you pay a deposit on the container. But when you buy another, you give them the empty and don't pay the deposit again.
I've been cycling my 3 carboys for years now. It's also worth it to spend the $3-$6 for a carboy nozzle.

[BigDave]

There's also a wrench available for tightening / loosening the cap and nozzle. You may not need it, but I no longer have the hand strength I once did and it really helps me.

[CarlD]

Channel Lock makes a great wrench that's perfect for it. Harbor Freight sells an oil filter wrench that should be perfect.