Does clarifier reduce or eliminate CYA?

[owkaye]

This year I put my new homemade sand filter into service. It's a 55-gallon plastic drum/barrel with the top cut off, and it sits up on a platform so the barrel bottom and pool top are at the same level. A PVC manifold in the bottom of the barrel is connected to a 2-inch outflow port through the side. The barrel is 2/3 filled with aggregate -- pea gravel on the bottom and sand on top. Water is pumped from the pool into the top of the barrel. It flows by gravity through the sand and gravel, then it enters the manifold and exits the barrel through the 2-inch outlet port.

I designed this system with these features in mind:

- it will (hopefully) make filter cleaning an annual off-season event rather than a monotonous daily task
- it uses gravity rather than pump pressure to filter the water, so it saves on electricity
- it eliminates the ongoing expense of buying filter cartridges

I filled the pool 5 days ago. The water started out very cloudy because I failed to wash the sand/gravel before putting it into the barrel. The water was gradually clearing for the first 2-3 days but then it stopped getting clearer -- likely because the filter cannot trap the microscopic suspended particles causing the cloudiness. This makes me consider the use of a clarifier, but this brings up a couple questions:

1- If I use a clarifier will it eliminate my CYA?

At the beginning of each season after filling the pool, I add a little dichlor each day as both CYA and sanitizer. My currently CYA level is 30-40 ppm, but if I use clarifier and it causes my CYA to coagulate and be filtered out I'll have to add more dichlor to get my CYA back to 40 ppm. So if this is a possibility I would like to know in advance.

2- Is there a better approach than using clarifier?

I know my cloudiness is not caused by algae because I've kept my FC at 4-7 since I filled the pool, and my CC has been zero every day. So clarifier seems like the proper solution in this situation, but if anyone knows of a better solution I'm anxious to learn more about it.

 

[tim5055]

You have found the Achilles heel of your slow flow gravity fed filter, it's slow. We seldom recommend clarifier - it is just more muck that will have to be filtered out of the pool, but no - it does not consume CYA. Heck, if it did we would be recommending it for all those pools with too much CYA.

Time and filtering is the solution, not clarifiers.

 

[owkaye]

No - it does not consume CYA. Heck, if it did we would be recommending it for all those pools with too much CYA.

Good point!

You have found the Achilles heel of your slow flow gravity fed filter, it's slow.

It's not slow at all. The water is draining out of my filter as fast as my pump can pump it in!

We seldom recommend clarifier

I understand this. I also understand that very few people use gravity-fed sand filters. Therefore my situation is unusual, and it seems to me that clarifier may be ideally suited to this application.

It is just more muck that will have to be filtered out of the pool

I'm sorry, but I do not understand your point. What 'muck' are you referring to?

The entire purpose of a filter is to remove the stuff (muck?) you do not want in your pool, correct? So what's wrong with using a chemical that causes the smallest particles to stick together and grow large enough to get stuck in the filter instead of forever being suspended in your pool water?

Time and filtering is the solution, not clarifiers.

Time and filtering will never work when the suspended particles are so small that they easily flow through the large voids between the sand grains, correct?

It seems to me that I have a unique filter with sand that's too large to trap the smallest suspended particles. Personally I think this might be the ideal time for me to use (and for you to recommend) a clarifier, especially when it does not consume CYA -- which was actually my biggest concern before creating this thread. But if there is a genuine reason for me to not use clarifier, please explain so I can fully understand the practical reasons for not using it.

 

[Flying Tivo]

You can add some DE to your sand filter for smaller particles.

good luck

Felipe

 

[tim5055]

It seems to me that I have a unique filter with sand that's too large to trap the smallest suspended particles. Personally I think this might be the ideal time for me to use (and for you to recommend) a clarifier, especially when it does not consume CYA -- which was actually my biggest concern before creating this thread. But if there is a genuine reason for me to not use clarifier, please explain so I can fully understand the practical reasons for not using it.

Did you use properly sized pool sand for your filter? There is a difference in the size of the sand particles.

If you did, the next step we recommend is to try adding DE to the sand filter. Pool School - Add DE to a Sand Filter

Obviously, with your filter you will not be able to determine the correct amount of DE to add based on filter pressure rise.

But your statement

I know my cloudiness is not caused by algae because I've kept my FC at 4-7 since I filled the pool, and my CC has been zero every day.

is not necessarily correct. The only way we accept that there is no algae in the pool is by passing the Overnight Chlorine Loss Test.

Were I you I would conduct an Overnight Chlorine Loss Test tonight. If the pool passes I would move on to DE. This is what I use in my sand filter. Pro Guard Cellulose Fiber D.E. Filter Media for Swimming Pools

But, with all that being said you do have a unique situation with your filter. One of the basic tenets of Trouble Free Pool Care is: - Never put chemistry in your pool when you do not know the outcome.

 

[cfherrman]

Get a small cheap sand filter(and maybe pump), around 12" - 13" with proper sand, clear out the pool with that, then you can play with your homemade filter. I went this route a few years ago and built my own stuff and basically wasted a month. eBay and $117 and zero time wasted after that pool was clean until I sold it end of last summer.

 

[Donldson]

Your pool is 1200 gallons. The cheapest and fastest solution is to dump the water and start over.

 

[JoyfulNoise]

In your situation with that homemade filter, a clarifier might or might not work. Clarifiers are mainly polymeric substances that attempt to bond small particles together by eliminating the electrostatic repulsive forces that develop on a particles surface (surface charge). They can sometimes clump up into particles big enough for a sand filter to capture, but not always. Eventually the polymeric clarifier breaks down again and the particles are released. So, even if you did manage to clear the pool with a clarifier, how would you backwash the filter to remove the particulates permanently?

What you would be better off using is a flocculant in your pool (simple alum floc) to cause all of the fine suspended particles to drop to the bottom of the pool where they can be vacuumed to waste using a small, low speed vacuum. HOWEVER, as JD pointed out, your pool's volume is so small that you would like pull half the water out vacuuming to waste.

While TFP appreciates the DIY spirit demonstrated by many folks that come here, your gravity fed filter design is not properly matched to the pool you have. You would be much better off as cfhermann suggested in finding a cheap sand filter on eBay to hook up to your 10' Intex pool. As you found out, the filters that come with Intex pools are cheap and mostly useless and many people simply ditch them and use a small sand filter to keep their pools clean and clear.

 

[owkaye]

What you would be better off using is a flocculant in your pool (simple alum floc) to cause all of the fine suspended particles to drop to the bottom of the pool where they can be vacuumed to waste

Does alum flocculant eventually release the coagulated particles like clarifier does? If not, what would be wrong with vacuuming into the top of my sand filter? Then I wouldn't lose any of my water.

The description of Leslie's Alum Enhancer Flocculant says it's good to use as a sand filter additive, so I would assume that vacuuming the coagulated particles into the top of my sand filter might be a practical thing to do in terms of continuing to trap suspended particles after initial treatment.

 

[owkaye]

Your pool is 1200 gallons. The cheapest and fastest solution is to dump the water and start over.

You may think so, but refilling the pool will push us over the standard water allotment and cost us $20-30 alone. Then there's the time to drain and refill, and the time and chemical cost to start over from scratch and re-balance with more dichlor, acid and bleach. No, an $8 bottle of clarifier at Walmart would be cheapest (if it works) or maybe I can get alum flocculant for a similar price and try that instead.

 

[JoyfulNoise]

Alum floc will gum up the sand as much as clarifier and eventually breakdown and rerelease the particulates. Flocs must always be vacuumed to waste.

A small sand filter would be better for your pool but if you don't want to do that then, by all means, try the chemical route (clarifier or floc). We'd be happy to see your results and conclusions. As you say, it's only $8 and so what's the downside other than it not working and you lose a cup of coffee or two at Starbucks....