No, you never need to shock. If you maintain the proper amount of chlorine in the water you should be fine. See this - [FC/CYA][/FC/CYA]
Your thought of finding a less expensive source for chemicals is a good one. Pool stores are known for selling you numerous white bottles of pool chemicals that had mysterious names and purposes to cure whatever today's pool water testing found. Unfortunately the pool industry has evolved into sales by scare tactics, misdirection, misinformation and marketing hype. Go in to the store and tell them your TA is low and they are going to sell you baking soda in a fancy package at four times the cost of WalMart. Do they have a right to make a profit, yes - but lets be reasonable. Heck, even their definition of "low" can many times put you on a pH roller coaster that's hard to get off of. Is that lack of knowledge or a sales technique to sell you more chemicals to control your pH????
What do we propose? We base our pool care system on accurate testing and only adding what the pool needs, when it needs it. Which leads to
TFPC tenet - Never put chemistry in your pool when you do not know the outcome
For almost everything the pool store sells, there is a generic "twin" that you can get at your grocery store or big box store. Alkalinity low? you can go to the pool store and buy Alkalinity Up in a fancy bottle or you can stop by HEB and pick up baking soda.
So, to control your pool you need to know what is going on. many folks have a Saturday morning ritual, dip a bottle of water out of the pool and take it to the pool store (they give you the bottle for free). They test it and sell you what they say you need to "fix" what ails your pool. But, you will find not much credence is given to pool store testing around here. While you would think that a "professional" would be the best, unfortunately in most cases it is quite the opposite. Between employees who blindly trust the word of chemical sales representatives and high school kids working in the pool store for the summer you end up with poor results from their testing. Plus, the results of their "testing" is used to convince you that you need to buy things. Why do you think that testing is free?
But, what can you do?? You need your own accurate test kit! Order a
TF100 test kit. The only other real option for a test kit is a Taylor K-2006-C. Be careful comparing prices because the K-2006 comes in sizes, designated by a letter. The basic K-2006 has .75oz bottles. You need to get the K-2006-C to get the larger bottles that you want. Even then it is a little short on the reagent & powder for the FAS/DPD test.
While entirely optional, I also have the
SpeedStir and
Sample Sizer. They speed testing and accuracy.
I see yo have a ColorQ. We have had members attempt to use the ColorQ to follow our methods and almost all have abandoned its use due to inaccuracies and inconsistencies. We even had one member test the same sample of water three times in a row and ended up with three different sets of results. Here is an example of a ColorQ post:
ColorQ vs TF100 and here is a review where the Color Q was used alongside a TF-100.
Test Kit Comparison
You have a chlorinator that uses 3" tabs. We really are not against their use, but we are against their uncontrolled use. The pool store tells you that they are the easiest way to get chlorine in your pool. They are. But, they don't tell you (or really don't understand) that the 3" tabs also add CYA (also known as stabilizer or conditioner) to your pool. In Texas you need stabilizer, but not too much. Others here can give you the scientific details if you want, but lets just say CYA locks the ability of chlorine to sanitize. The more CYA you have the more chlorine you need to keep in the pool to keep algae at bay.
While talking about chlorine understand, chlorine is chlorine is chlorine. The chlorine in bleach is the same chlorine in the 3" tabs and is the same chlorine that is produced by a salt water chlorine generator. They are just different methods of adding the chlorine to you pool water.
So, TFP is not "against" anything - it's "for" knowledge. The knowledge is condensed in the
Pool School link at the top of every page.
How much
Pool School have you read? Start with these:
ABCs of Water Chemistry
Recommended Pool Chemicals
How to Chlorinate Your Pool
So again, welcome to TFP!!