Converting to SW - do i have to drain first?

[forbesie]

What a great resource this board is, I wish I had found it sooner.

I'm converting my hydroforce steel frame 18 x 48 and adding a hydroforce/bestway SWG which seems pretty straightforward, however, my pool is currently pretty green, should I try to fix this before converting? drain, clean and re-fill? or just switch over to salt-water and go from there?

Any help would be much appreciated as I am hoping to have this up and running by Sunday.

Thank you.

 

[svenpup]

You don't need to drain. Post a full set of numbers so we can determine what your best course of action is.

 

[JasonLion]

Welcome to TFP!

As svenpup said, more information will help a great deal. In general, it is easier to fight the algae than to drain, however there are several factors that come into that decision that will be apparent if we see a full set of water test results.

 

[forbesie]

I used a test strip and came up with these:

ph 7.8-8.4
ppm free chlorine 5-10
alkalinity 120-180
stabilizer 0


thanks!

 

[svenpup]

I suggest a good FAS/DPD based test kit with with CYA. There is a test kit comparison in Pool School, with the TF-100 being the best deal.

You should also add either a salt test kit or salt test strips if you are going to SWG. Your salt is certainly not zero now.

Without knowing CYA and CH we can't really recommend whether to drain or not. Also, without knowing CYA, you can't properly maintain your pool or fight the algae you have.

An SWCG does relieve the pool owner of some of the daily maintenance chores, but it is not a hands off solution that allows you to ignore pool chemistry.

Your first course of action is to get the algae under control following the instructions in the "how to shock" link in my signature.

 

[JasonLion]

svenpup, stabilizer is CYA, so CYA is zero.

Your numbers look reasonably good, they need some minor adjustments, but I don't see any reason to drain and replace the water. You can if you want to, it might be faster, but I wouldn't.

 

[svenpup]

Oops...missed that

 

[forbesie]

svenpup et al, thank you for your help, i'm definitely learning a lot.

It appears to me that since CYA is zero and FC is 10, then I am at or above shock level already and shouldn't add anymore chlorine, correct?

So if my numbers appear to be good, what else can I do? Or should I go ahead and hook up my SWG and add salt?

 

[svenpup]

forbesie, how have you been chlorinating up to this point?

The likely reason for your algae is that all your chlorine is burned off in the sun, so you go to 0 FC every day.

Recommended CYA levels are 30-50ppm for non-SWG, and 70-80 for SWG. Either way you need to bring it way up.

My other comments stand though. A good test kit is going to be invaluable to you.

I think you should get your pool under control before moving to an SWCG. You can't shock with an SWCG and you need to shock (to completion) now. Remember, shocking is a process and not a one time spike in FC. You need to hold it at shock level until the algae is all dead, and this will be hard to do if the sun is quickly burning it off.

You could bring the CYA up to 20-30 to help complete the shock process. Then once the pool is clear and you want to switch to the SWCG you can bump it up to 70-80.

 

[forbesie]

Sounds like I should pick up some CYA tomorrow.

To answer your question, I chlorinated last night and then again this morning around 7AM and the measurement of 10 CF was from 830pm, so could there have been much of a burn off? It was a mostly overcast day here in Ottawa today.

Is it worth it to bring a water sample in to a pool store at this point?

Also, from what I've briefly read, it can take up to a week for CYA levels to appear on tests, it would take me less time than that to drain and re-fill my pool and convert to SWG...

 

[JasonLion]

If CYA is really zero, then yes you will lose all of your chlorine over the course of a day, even if it is somewhat overcast.

 

[svenpup]

You can drain if you want to...it is always a viable option. We were just trying to explore your best choice. If you do drain, I still recommend shocking right after anyway, to make sure you get all the algae that will still be in whatever water you don't drain and all the nooks and crannies.

I personally would bring CYA up to 20-30 and shock.

The CYA does take up to a week to show up on tests, but we recommend 'assuming' the target CYA level 24 hours after adding it. You will be getting at least some of the benefit at that point.