New IG pool owner, filter questions, checmicals to start etc

Mar 21, 2008

We bought this house last November, and it came with a 16x32 vinyl liner IG pool. I'm about ready to start opening it for the first time, and I'm kinda lost.

On the filter/pump: It's a "Sta-Rite Cristal Flo" sand filter. Found a manual for that. To open the winterized pool, is it necessary to backwash/rinse? My major dilemma is the plumbing. There are two pipes coming out of the ground that meet at a valve, then go to the pump. There's one setting marked on the valve - "OFF". What does this valve control? I'm guessing it's to set either bottom drain or skimmer input, but I'm hoping someone can enlighten me. And, if that's the case, do you usually have this set to bottom drain position, unless skimming/vacuuming?

Next, chemicals: I used to own/maintain an AG pool years ago, so I'm not 100% unfamiliar with this, but... Lots more water, and it's in-ground (doubt that matters, but it's a lot more expensive to fix IG's than AG's, so I don't want to mess up). I'm guesstimating it's about 23,000 gallons (16x32, 4ft sloped to 9ft). Here are my test results:

FC = 0
Total Bromine = 0
TC = 0
CC = 0
pH = 6.5
Total Alkalinity = 10ppm

Where do I start? I want to use the BBB method, but I'm unsure if they need to be raised in any certain order... I want to "shock" the pool tomorrow to get the chlorine levels up to start killing some of the greenies, but do I also try to raise the pH/alkalinity/bromine at the same time? Is Borax B in BBB that raises bromine levels? How much "stuff" am I going to need to get these levels where they need to be?

Thanks in advance for your replies. I'm feeling a little overwhelmed right now. :)

First thing you need is a better test kit since you also need to be testing your calcium hardness (calcium is not needed for a vinyl pool like it is for a plaster one but it's still importants--it can be too high or too low and either one can cause problems) and CYA or Cyanuric acid. This one is IMPORTANT to know. Most of us here use the TF100 testkitor a Taylor K-2006, both have the superior FAS-DPD chlorine test tht you are really going to need once you start shocking!
Ignore the bromine reading, Bromine is a different sanitizer and you are not using it. Most chlorine tests can also test bromine and the result is about twice as high so they include the bromine scale.
Borax is used to raise pH without having a major impact on Total Alkalinity, it is also used in a 30-50 ppm level in the water as an algaestat and pH buffer but that is an advanced topic.

I suggest you start by reading The Stickies from the menu at the top of the page to get an idea of where to start and what things mean. I would read every one of them and if you don't understand something then just ask!!!!

Until you actually KNOW the CYA level you don't know how high you need to shock (or can safely shock with a vinyl pool) to take care of the 'greenies'. If you order a TF100 test kit you will most likely have it in a few days since Dave is very fast at shipping them out!

I get about 18000 gal for your pool if it is rectangular. (32 length x 16 width x 4.5 average depth x approx 7.9 gal/cubic foot = 18201 gallons. If it is oval, freeform, or the slope of the bottom is not even but 'drops off' at the deep end then your gallonage is going to be smaller.

The two pipes that go from the three way valve to your pump is most likely to control the drain and skimmer if they go to the suction (input) side of the pump. Normal setting is half drain and half skimmer. Start there and then make adjustments and see if it affects how clean your pool stays. Some systems need the main drain shut off when vacuuming. You will have to experiment and see if you have enough suction with the drain left open. If not then just shut it when you vacuum.
Mar 21, 2008

Thanks for your reply. I just spent the test kit budget on a Taylor DPD deluxe kit, so, I'll take it slow and easy with the chlorine, and figure the other levels out as a learning experience. (Not that I wouldn't mind having the CYA test, too, mind you, but money's tight and all that...) :) The cover's still on the pool, so I may get pleasantly surprised by what's underneath. :)

For average depth I used (shallow depth (4) + deep depth(9))/2, which I read elsewhere as the formula for the calculation.

I'm attaching a picture of the valve in question. It rotates 360 degrees, and there is only that one "OFF" marking, so I'm kind of confused as to what position it should be in for half & half. Maybe you can tell by looking at it. I just don't want to flip the switch and have it explode, or anything. :)

Anyways, take a look if you have a minute... And I'll gladly take any advice you have for chlorination minus a CYA measurement! :)




TFP Expert
LifeTime Supporter
Mar 29, 2007
Coastalish 'down easter'
JB, welcome to TFP!!

Waterbear is right about the need for a good test kit!!!

However, you also wanted to know what to add tomorrow to start the process. I think that you can safely add 2 gal of 6% bleach, 2 boxes of Borax and 10 lbs of Baking Soda as a starting point. You need some cl in there STAT and the 6.5 pH is harming your liner! I have purposely 'downplayed' the amounts because we are unsure as to the cya, pH, pool volume and your test kit - however, I believe that if you add what I advised, the numbers will be a LOT closer to good than they are now, with a very small chance of 'overshooting' ! While you're out, pick up 4 gal of bleach, but add only 2 for a start - you'll probably need it before very long :wink:

As for the valve before the pump, it's normal place would be to have both the skimmer and the MD open (50 - 50 is a good place to start), but you may want to 'tweek' it some to get more or less suction from the skimmer (the skimmer is the 'first line of defense' against stuff ending up on the bottom of the pool - if your skimmer can catch any debris before it sinks, you'll have to vacuum less frequently) The valve you have can also be used to maximize vacuuming efficiency (here's how-- hook up the vacuum to the skimmer without changing the valve, then go over to the system and close the MD port slowly, until you see ~ 1/2 lb psi drop on the filter's pressure gauge -- then you are all set to quickly and easily vac the pool, without the vac not getting some of the debris or sticking to the floor from too much suction)

Don't feel overwhelmed :!: There are a ton of great and friendly folks here to help with just about any problem you may encounter -- we're somewhat of a family here and do our best to help each other - Welcome to the family!! :-D

(PLEASE remember (!) - the only dumb question is the one unasked!! (No one is born knowing how to take care of a pool!!)


TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
Silver Spring, MD
Welcome to TFP!

I suggest you start with 8 to 12 lbs of baking soda and see if you can get your PH and TA up to more reasonable numbers. First priority is to get your TA to at least 50 and PH to 7.0 or higher. More precise adjustments can wait till later.

It is very difficult to guess how much chlorine you are going to need without knowing your CYA level. Starting with 2 gallons of 6% bleach and then adding 96 oz (a small jug) every day in the evening is a reasonably safe place to start. You need to get some idea of your CYA level. You can either purchase a CYA test kit, TF Test Kits sells the CYA test alone as does Taylor and several others, or go to a pool store and get them to test the CYA level. Money on a test kit is always well spent, you will more than make up for it in easier pool care and chemical savings.



Well-known member
May 20, 2007
Houston, Tx
i got a cheap CYA test from wally world for $10, it was test strips and had other things on there, but none of them i would put much value on. the FAS-DPD will be much more accurate than the HTH test strip, but for $10 for 50 strips to get an idea of CYA isnt a bad idea. or you can take it up to local pool store, but from my recent experiences, i have figured out they are typically way off and pretty useless.
I repeat, you need a good test kit. It will save you a LOT of money in the long run and is going to be the best $80 you spent on the pool!! Without good test results you really don't have a clue and with a vinyl pool, if your chlorine levels are too high during shocking you can bleach the liner. DPD can bleach out at shock levels or read low which is why we recommend the FAS-DPD test. The other tests ARE necessary. You can add just an FAS-DPD, calcium harness, and CYA test to your kit but it might cost your more than getting a whole new kit.

Without good test results you have nothing.

As far as your valve, the handle points in the open direction so when the handle is not pointing to any pipes (like in your picture) it is off or closed. If you turn it around 180 degrees so the off and handle sides are transposed you will be at the 50-50 position.

Finding out your CYA level is very important since your pool has an inline chloirnator and has most likely been maintained on trichlor. The possiblility that your stabilzier levels are way too high is very great. If you don't find out before you start trying to clear it up you could waste a lot of chlorine. Getting the testkit you need from the beginning is the sensible thing to do.

Get your pH up ASAP since a pH that low can ruin your liner!!!!! (if it hasn't already happened :shock: ) THAT is what borax is for in BBB!!!! But in your case since BOTH pH AND TA are low I would use soda ash. Add a pound, wait a few hours and test pH and TA, repeat until pH is above 7.0 and post your numbers and we can take it from there.
Mar 21, 2008
I get the idea - test for CYA level. :) Ordered a CYA test kit, should be here Wednesday. Funny thing - had an AG pool for 20+ years, always crystal clear, always perfect pH/chlorine levels, and never knew boo about CYA, alkalinity, bromine, etc., etc. And only replaced the liner once. Lucky, or am I just THAT good? (Your opinion may differ from my own.) ;)

I will, however, start tackling the low pH / TA tomorrow, and add a minimal amount of chlorine until the test kit gets here. If the CYA level is too high, I don't mind draining it off. Bleach is pretty reasonable. So, by mid-late next week I can post some revised measurements, WITH a CYA level. When I start adding the chemicals, I'm assuming that the filter should be set to "re-circulate", not "filter" right off the bat, is that correct? The pool is located far away from any trees, so hopefully the bottom won't be all gunked up with big stuff. Would pumping off the top of the cover make any sense, or will the water just pass through faster than I can pump it off? It looks like it's seen its better days...

Also, thanks for all the replies on the pump plumbing question - I think I get it, just gotta figure out which way is full drain vs. full skimmer. How do you release pressure on those things? A quick look and I didn't see any obvious pressure release valve...

We saw the pool last season as the previous owner was shutting it down, and it looked immaculate. Hopefully he knew what he was doing, but all we found as far as testing gear went was a bottle of test strips. Don't even mention the possibility of a damaged liner - if that was the case we'd fill it in with topsoil and have a larger garden. ;)

Thanks again for all the help so far - seems like a great group of folks here. :)

JBowman said:
I get the idea - test for CYA level. :) Ordered a CYA test kit, should be here Wednesday. Funny thing - had an AG pool for 20+ years, always crystal clear, always perfect pH/chlorine levels, and never knew boo about CYA, alkalinity, bromine, etc., etc. And only replaced the liner once. Lucky, or am I just THAT good? (Your opinion may differ from my own.) ;)
I will guess thqt you had a smaller AG with a sand filter so you were pretty much keeping the CYA in equalibrium by luck. Also, I will guess that you used soda ash (pH increaser) when the pH was low. That would have kept your TA on the high side most likely, which is where you want it for trichlor. If you kept the pH above 7.0 and didn't shock to too high a level then having a liner last for 10-15 years is not uncommon.
Am I close? :wink:
BTW, what do you call 'perfect pH/chlorine levels'? If you didn't know your CYA then there is no way you could know if your chlorine was 'perfect'. If you kept your pH between 7.2-7.6 then you kept it in generally recommended range but not necessarily optimum levels.
Mar 21, 2008
21' round, which dropped off to 7' at the "deep side". It was a Hayward filter - one of those paper-like cartridge jobs. Pool store "shock", bleach, baking soda, and a bottle of algaecide a handful of seasons. That's it. Never red eyes, and you could always tell heads or tails on a dime at the bottom. I graduated from test strips to a reagent-based pH/chlorine test kit probably 10 years after the pool was installed. Only replaced the liner because of two rust spots which worked through to the sand underneath, and only junked the pool because the walls started to to get "wavy" at the base, like it was getting crushed (walking along the rails to vacuum probably didn't help that much).

Maybe water's gotten more complicated since then, but that's the way it was, swear to god. :)


chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
San Rafael, CA USA

So did you use the pool store "shock" bleach (which is probably 12.5% or possibly 10% chlorinating liquid) as your regular source of chlorine? If so, then that would explain your good results since that is essentially the BBB method. One does not have to use actual bleach from the grocery store. I use 12.5% chlorinating liquid from my local pool store because it isn't that much more expensive and they reuse the bottles (so less waste/recycling). That's pretty much all I use all year long except for a small touch of acid every couple of months -- I don't need nor use algaecide.

The continued rise in CYA would only occur if you used Trichlor tabs/pucks or Dichlor powder. If you just initially added CYA to the water (which I suspect you did; otherwise the chlorine wouldn't last long in sunlight) and then used pool store "shock" bleach after that, then you were golden.

Mar 21, 2008

Never poured CYA into anything. :) I remember like it was yesterday - 4 gallons of "shock" (which was the 12% stuff) to open the pool, then 1 gallon every Sunday, and 2 scoops of "Super 95" (brand name? chlorine granules) every three days. The pool looked great, the test kit read good, I didn't need goggles, and the liner lasted longer than it should have. If I can get the same results with this pool, I'd be more than happy.