K.I.S.S!
EDIT: After reading through this a second time I moved this thread to a more appropriate section of the fourm
Waterbeear, TFP Moderator
All I am going to say is that there are those that like to make pool care a lot harder than it really it. If you want to see a prime example of what I mean by micormanaging see the above post!
You have to take into account the precision of the testing methods that we use and where the point of diminishing returns comes in.
Just because your test result says that you have 100 ppm TA does not mean that you do. It could be 90 ppm or 110ppm. If you are using a smaller sample size that same 100 ppm could now be as low as 75 ppm or 125 ppm. If you are going by the pool store results with their fancy machines it could even be worse than this. Case in point is LaMotte's CYA test with their Waterlink System. This has a precision of +10/-25 ppm so when the printout says you have 48 ppm CYA it could be as high as 58 ppm or as low as 23 ppm!
Don't know what kind of skimmer you might have but my Hayward skimmer works just fine with the water an inch from the bottom or an inch from the top of the opening so it's about a 4 inch variance. A 2 inch difference in water level in a pool is very common unless you have an autofill and overflow drain and in that case your chemical levels will be changing all the time anyway. Unless, of course, you micromanage by making sure that you always have exactly x inches of water in the pool and if it is off by more than 1 inch you correct it immediately
While a pool does need to be kept withing certain parameters to be trouble free there is some latitude. Just because a chart says that you must keep your FC at 4 ppm because your CYA is such and such does not mean the world will end if you have 3 ppm or 5 ppm and, with the testing accuracy you very well might. When it says that you need to shock to 16 ppm it does not mean that shocking to 20 ppm is going to be a problem. I have seen a trend develop on this forum for making simple things much more complicated than the need to be.
I see newbies stress all the time about adding CYA because they are so afraid of overdosing. Just figure out what you need for 40 ppm and put it all in and don't test it for a week. If you misfigured the volume of your pool you will still be in an acceptable range unless you REALLY blew it on the volume. In that case you now know that your first step is to find the actual volume of your pool. However, that is a rarity.
Just because the pool calculator tells you you need 54 oz of CYA (which work out to 3.4 lbs) are you really going to weigh out 4/10 of a pound or are you going to add 3 and a half lbs. And do you really think that .1 lb of CYA is going to make any real difference in your pool? I bet that a lot of people will just put in 3 lbs or 4 lbs and call it a day. And you know what? They will be fine and so will their pools! Things like the pool calculator are tools, not rules! Personally I prefer the dosing charts from OnBalance since their formula only requires that you have a calculator with you and a table of their constants for the various chemicals. And guess what, the results agree with the pool calculator. I also use BleachCalc a lot. It as some bugs in the borate section but it's a useful program that works. I also use chem geeks spreadsheet. The point is I use all the tools available to me and use them as tools with a bit of common sense! Let's not forget that we are talking about a swimming pool and not a science experiment! The amount of precision that some people try to put into their calculations just ain't there because our test kits don't have that much precision! Once people realize that they will stop sweating the small stuff and enjoy their pool.
K.I.S.S.
The test kits we recommend are not ambiguous so it is east to get accurate (repeatable) results. The precision is enough for what we are doing, maintaining a swimming pool but it is by no means anywhere near precise enough to worry about a difference of a few hundred gallons in any pool over about 8-10K gallons. Even in my own less that 7k gal pool and spa it really doesn't make that much difference in my test and dosing results whether i call my pool 7k, 6k or the actual 6850k
Finally, the term 'advanced beginner' is an oxymoron. You are either a beginner or an advanced pool owner, not both. If there are principles of pool care that you don't know or are not sure about then you are a beginner. If you can stand on your own and know what to do and why without asking for help when things go wrong then you are advanced. If you don't have a clue as to the difference between calcium and chlorine and you use the term "pool thingy" a lot when referring to the equipment you are a newbie.
Once again, don't make it more complicated that it has to be by creating "CABs" AND "NNs" What is the next step after CAB? Beginning Intermediate Techno Chump?
Thank you for making my case for me!
K.I.S.S.
Now as I see it I can either continue to waste time here debating this with you (not to mention the time already wasted with the PMs) or I could spend my time moderating this forum AND trying to help people with their pools. Ask any of the mods how many man hours (or woman hours) we need to put in to keep things running smoothly around here on a daily basis. We do this because we want to, we don't receive any compensation or anything. And for that matter I believe that I am the only mod that has been modding continuously since the inception of this forum. And you have been a member for what, 6 months now? If I remember correctly you came here with high CYA and were using trichlor. You even asked about using trichlor in your spa. Perhaps in a few years we can continue this once you have 'gotten your feet wet' so to speak.
K.I.S.S!
