New (to me) Indoor Pool - how to sanitize?

[jeremy]

So we recently purchased a home in NY with an INDOOR pool. Here are some stats for the pool and pool house:

• 33' x 22', 3' shallow end, 9' deep end

• DE Filter (48 sqft)

• Manual crank safety cover for safety (duh) and to keep evaporation and heat loss to a minimum

• pool house is about 2400 sq ft with 10'-25' ceilings

• surrounded on 3 sides by glass doors/walls

• fourth side is entrance to house - 4 doors

• Climate controlled

• 8 remote control open/close skylights

• 8 closed skylights

• lots of natural light, but not a lot of direct sunlight, other than what makes it through a couple skylights for a few hours a day

Here is the big one - it is set up with an ECOSmarte system, but I am not convinced that it is worth keeping.

So the question is, what do I do now? The water looks pretty clear, but I dont trust that it is safe to swim in. And even if I get the water safe to swim in today, I am not convinced any amount of regular maintenance will guarantee that it will stay that way. I am looking for advice on an alternate method of sanitizing this INDOOR pool.

Regarding test results, I dont trust these because I used 4 year old test strips. New ones on the way:
FC - 5
CC - ? (Total Chlorine is 5)
pH - 8.2
TA - 180
CH - 100
CYA - 150

The pool company came one time since we bought the house. They put in 2 gals of chlorine pool shock about 3 weeks ago.

Not sure what else to say. Thanks for your input!

 

[Isaac-1]

Indoor pools are a bit different than outdoor, still I strongly suggest reading the pool school link in the upper right a couple of times (most people get a lot more out of it the 2nd or 3rd time through). It sounds like your indoor pool is set up fairly similar to mine (mine is not attached to the house though), surrounded by sliding glass doors and an overhead skylight (my polycarbonate skylight is 6x40 ft) while this does let a good bit of light in UV blockage is around 90% so there can be some issue of CC build up.

As a general rule you can follow the suggested TFP chemical levels, but keep CYA between 20-30 ppm and maintain FC in the rage specified by the CYA/FC chart. Standard industry practice is to not use CYA in indoor pools, which results in FAR higher active chlorine levels than needed, ruining bathing suits quickly, etc.

For chlorination I am currently using a bleach / liquid chlorine and an injection pump, during active swim season I use around a quart of 6% bleach per day, although this does vary with bather load. To deal with the lack of UV exposure in an indoor pool and buildup of CC, you have basically 3 choices, a UV water sanitizer system, a ozone injection system or you can chemically treat the water with an MPS non chlorine shock product. I personally don't see a big advantage to any of them, and just bought an ozonator a couple of years ago because I found it listed on ebay still new in the box at about 80% off new price.

Ike

p.s. where did you get those test numbers from, if your cya is really that high it looks like you will need to do nearly a complete water replacement to get it down to reasonable levels (anything under 50, but as I mentioned above 20-30 is better for an indoor pool)

also most pH tests only read up to about 8.2 so a reading of 8.2 could be 8.5, 8.9, ...this is the first thing I would address getting it down into the 7.5 range by adding acid

 

[jeremy]

My number one concern with using bleach / chlorine is the potential for odor in the house. We like the idea of being able to leave the doors open to the house from time to time. How can that be avoided?

Regarding the tests, I am new to this. It's from a years-old 7-way test strip. I ordered some new ones but now I see TFP recommends other types.

I also ordered some acid and will have it soon.

Can you clarify a bit though what equipment change I am looking at? I don't know much about injectors, ozonators, etc. And then there are salt systems...?

 

[Isaac-1]

AH, the "Chlorine Smell" this is a VERY common misconception, you are not smelling chlorine, you are smelling combined chlorine products that are often the result of too little active chlorine in the water for your CYA level.

A quick proof of this is to go open a bottle of standard household bleach and carefully sniff, you don't get "that chlorine smell" (well you might get a faint hint of it, but that is really the chlorine reacting in your nasal passages forming combined chlorine products.

A well balanced pool will have almost no smell to it at all.

Ike

p.s. I would strongly advise against a salt water chlorine generator for an indoor pool, salt water is more corrosive than fresh water, and the last thing you need with an indoor pool is more corrosion potential. As to chlorine injection I am using an LMI brand metering pump, there are also a number of people here using stenner peristaltic pumps, most of the experts say the stenner pumps are the better choice, lower maintenance costs, etc. There are a number of message threads you can search here for opinions on chlorine injection pumps, on first thought the addition of an injection pump may be all you need, but every pool is different, some need acid injection to maintain pH, which yours might, but we will know more once you get a good reliable test kit, some good numbers, and some experience on how yours trends over time etc.

 

[jeremy]

ok. Saltwater = bad for indoors. got it.

The idea behind these injectors - chlorine and/or acid - is that to give consistent levels without having to add it on my own? Is it a necessity or is it for convenience? Is it specific to indoor pools?

Something to consider: we don't swim a lot. At least not right now. And with 3 kids under 4 years old, we keep the (manual operation) safety cover closed ALL the time.

P.S. Thanks for the direct advice. I plan to browse the threads suggested when I have some time.

 

[Isaac-1]

Chlorine injection is a convenience, over the years I have done just about all the chlorination methods other than SWG, I started with pucks, then bleach, baqua, pucks, and now back to bleach with the BBB method which has been working well for me the last 4 or 5 years. I find it allows me some freedom from daily pool tasks, allowing me to go 2-3 days between testing during the active swim season, it also allows me to be away from the pool for up a week at a time without any major fear of things getting too far out of balance. Without some type of automatic injection system bleach become a daily chore as a method of maintaining proper chlorination this is part of the reason so many people see pucks as appealing, as they give a perception of less work.

Ike

ps My immediate advice is to go ahead and get a good test kit on order I suggest the TF-100, and if you have one get that pH problem under control before it does damage to your pool or equipment

 

[chem geek]

If you use some CYA in the pool, then the active chlorine level will be 10-20 times lower and will outgas that much less as well (assuming you don't have the pool covered). So you shouldn't smell the pool as much, not even the faint bleach-like fresh chlorine smell. Indoor pools that don't use any CYA tend to outgas chlorine a whole lot faster and that's what you smell (or as was pointed out you smell that chlorine reacting with ammonia in the sweat in your nose and you smell these by-products).

Because the pool is not exposed to sunlight, you may need to use some supplemental oxidation. UV is common, but you could use non-chlorine shock (MPS) as another alternative when needed. It depends on how much you use the pool. You might want to keep the FC somewhat higher than for an outdoor pool so at or above the target FC in the chart rather than at the minimum. Again, this depends on your pool use. You can try the minimum and see how things go, but if you find Combined Chlorine (CC) forming then you can use a somewhat higher FC level along with some supplemental oxidation/treatment.

 

[jeremy]

we will pretty much keep the pool covered unless someone will be using it.

does the oxidation of the exisitng EcoSmarte system work? thats already installed, although I will not use it if it doesnt work or if it isnt appropriate.

 

[chem geek]

The ECOsmarte system just uses platinum plates so their oxidation mostly produces oxygen gas and a small amount of chlorine (depending on salt level). It is not composed of boron-doped diamond electrodes that produce larger amounts of hydroxyl radicals (powerful oxidizers) nor is it an ozonator. So unless they've changed their design recently, their oxidizer is next to worthless in spite of the pseudo-science on their Science Summary page.

Also, that system usually adds copper ions to the water as well and these can stain pool surfaces (especially plaster) if the copper level gets too high or the pH gets too high. If you have a choice, I'd at least disconnect the copper bar part of the system. As for the oxidizing part, you can just see if it does any good for you. The only side effect it might cause is a rise in pH from all the bubbles (aeration) it generates, but with a cover that effect might not be so noticeable.

 

[jeremy]

So I finally received the TF-100 and was able to do a few tests.

First I tested the PH, and it was 8.2-8.5 (or higher?). So I added half a gal of acid and the PH went down to 7.5

This morning (2.5 days later):

• PH = 7.5

• FC = 10-11

• CC = 0

As I said earlier, the pool company added 2 gals of chlorine shock almost a month ago, and nothing else since. The pool has been covered, and no one has used it. DE filter runs 12 hours/day (8am-8pm).

Do these numbers make sense? What else do I need to test? Is the pool safe to use yet?

 

[harleysilo]

If you've not added chlorine in a month, and those are your levels, the pool should be and is algae free. The cover really helps hold chlorine in. What is your CYA level? How does the water look?

 

[jeremy]

I am going to run all the other tests tomorrow morning.

The water is mostly clear, a drop cloudy in the deep end (really very little), and mostly noticeable at night when the underwater lights are on.

There has been a small amount of brown "stuff" on the bottom in a couple spots. I brush it to the main drain, but haven't tried vacuuming yet.

I just got some DE powder delivered, so I can now backwash (and maybe clean thoroughly too) the filter. Never done either one before, and I am not 100% sure where the backwash ends up, so need to figure all that out.

 

[harleysilo]

So you've read this use-and-care-for-de-filters-t4086.html

On page 2 of that thread you can see pictures of how dirty my filter was after 1 year of only backwashing.

How a ya'll managed to stay out of the pool for a month!?! I'd be in every night if mine was indoors.

Just to be clear, your cover is a vinyl material, that doesn't have holes in it correct?

 

[Isaac-1]

Wow if your FC is still at 11 after a month they must have really sent it to the moon (probably lack of experience with indoor pools, plus their usual one dose nuking philosophy), hopefully this did not damage your liner, pump or other equipment too much, although I suspect it took a year or two off the life of the liner depending on what your CYA level turns out to be. If your CYA level is low you might want to consider buying some chlorine reducer (a little goes a long way) to bring your water down to safe swim levels without having to wait another couple of weeks for that to happen on its own.

Ike

 

[jeremy]

Aside from the fact that we are new (first-time) homeowners, and have been busy with a million and one things, I just wasnt sure about the safety of the water. This pool Had an EcoSmarte system installed, and I had been talking to the company about how to get it to work. During that time, I became convinced that it was not going to work and have moved to the chlorine method.

To be clear, the chlorine from the pool company went in a month ago while I was still exploring the EcoSmarte way.

We are using this cover: http://www.poolcovers.com/ And I assume by holes, you aren't referring to the kind made when I walked on this cover and my foot went through it. This is a vinyl saftey cover. Its going on 7 years old, and I am told its due for replacement. Just add it to the list...

In any event, looks like we're getting somewhere now. I will test CYA (and CH I guess) and report back here.

EDIT: Is the FC level safe to swim in? Should I be calling the pool company to yell at them?

 

[jeremy]

Also, this is the first time i did an FC test with the new kit. I will do it again in the morning, and see if i get the same results. Do i need to give the cylinder a thorough swirl between each drop? I was kind of just swirling around as i slowly dropped the reagent in.

 

[Isaac-1]

As long as there is still good water swirling action you should be ok on the method your using, personally I have been using a speed stir for the last year or two which takes the concern out of swirling technique. As to the safe to swim question, it depends on the CYA level, if it is above 30 then you are safe to swim now, otherwise I would get the FC a bit lower first.

Ike

p.s. remember the CYA test should be done outdoors with the sun to your back

 

[harleysilo]

Here is the link to the chart in pool school that shows the CYA relationship pool-school/chlorine_cya_chart_shock , once you know your CYA level you can use it to determine what your FC level should be, and up to what FC level you can swim (shock level for your cya number).

Sorry about the hole in your cover! Did you patch it temporarily?

I have only ever used the speed stir, sorry i can't offer advice on swirling other than to get the speed stir!

 

[jeremy]

p.s. remember the CYA test should be done outdoors with the sun to your back

does this mean i should walk outside? Or does it mean IF i am outside, the sun should only be to my back. It sounds to me like i should collect a sample, and then walk outside to do the test...

 

[jeremy]

Also, what is the greenish/brownish "stuff" I find at the bottom of the pool? Not a lot, but some, and all the brushing doesnt get rid of it.