Think im on the right track, just want some expert opinion.

[michael73]

Hello from Australia, southern east coast, Geelong, Victoria, the beginning of Autumn (fall) but still lovely weather (low 30's 86f), we have a 15000lt 4000gal, above ground plastic liner type pool, its been great for a few months, nice and clear, checking FC and PH daily, adding granular chlorine daily too, pretty sure its CAL-HYPO, recently bought a Hach brand strip-type test kit. But i prefer to test PH with the phenol red 5 drops on the color chart.

Anyhow the issue is the bottom of the pool will be a slight green (after 12 hours of not being used it settles), see attached pic, the water is clear but theres a layer on the bottom of the pool, i vaccuum it into the sand filter and most of it stays in the filter but some of it gets stirred up and the water goes a slight shade of green.

Seems its a algae issue, i like the PH around 7.6, when i SLAM the FC goes to over 20ppm, havent had the TC above FC yet. CYA is always low, towards 0. TA around 100, Total hardness around 250 (not that i know what hardness is used for)

This sediment on the bottom seems to be an almost on-going issue despite the FC staying above at least 5ppm after the Shock (above 20) and daily vacuuming.

When SLAMing how many days do i maintain high FC (10-20 or above) for?

 

[needsajet]

Welcome to TFP! Good to have you here

SLAM duration is hard to predict and can be anywhere from 3 or 4 days up to several weeks. It is often only needed once, and then it becomes easier and more reliable to manage the water chemistry and sanitation. Quick SLAMS happen when people follow the method well and filtration is effective. It gets slower when life gets in the way and the chlorine shock level is not maintained regularly.

To follow the TFP SLAM procedure, along with other parts of Trouble Free Pool Care, the FAS-DPD chlorine test is needed. A test kit with FAS-DPD is available from Clear Choice Labs. Products Clear Choice Labs

When I started out with TFPC, I found the first two posts in this thread helpful: TFPC for Beginners

The SLAM method is here: Pool School - SLAM - Shock Level And Maintain

Come on back with questions any time. There are lots of people here that love helping other pool owners because most of us have been in your (pool) shoes in the past!!

 

[pooldv]

Welcome to TFP! I'm ready for a lot more low 30s C and no more low 30s F!

After you successfully SLAM the pool if the clear and green persists then it could be iron in the water. We can work on that next if we need to. But, first we need to make sure there is no algae and the water is clear.

You can put your pool info in your signature so it shows up on each post. More here on what to add and how to do it, Pool School - Read This BEFORE You Post

 

[michael73]

Thanks for the welcome messages.

The water is clear but green sitting on bottom of the pool (see previous image)

I can vacuum most of it up but it's generally back the next day, but a little less. It's very fine because even vacuuming and stirring the water up makes some of it mix with the water and then the water has a slight green tinge.

 

[pooldv]

That sounds like algae.

 

[michael73]

Day 2, same as day 1, swept the bottom of the pool and the same green plooms come up into the water. FC above 10. PH 7.6

 

[YippeeSkippy]

But *how much* higher than 10ppm is your FC?? Do you have the tools necessary (the right test kit) to perform a SLAM??? See post #2.

Yippee

 

[michael73]

Thanks for your reply.

Can you explain what level FC I should be maintaining until the green is gone? TC is zero or very near. I'm using Hach test strips that on the high end show a colour for 10ppm and 20ppm.

Thanks ?

 

[Jezza]

You'll need to know what your CYA level is (aka stabilizer level) as this will determine your SLAM level of FC.
As mentioned you need the right test kit from Clearchoicelabs to identify the correct readings for CYA and then be able to measure for high levels of FC -the test strips won't cut the mustard.

 

[needsajet]

To do a SLAM, you maintain a free chlorine (FC) level relative to your level of stabiliser (aka cyanuric acid, aka CYA), per this chart: Pool School - Chlorine / CYA Chart

The Clear Choice Labs test kit includes a CYA test. This is your best choice in Australia: Total Pool Water Testing Kit, Fresh Water Clear Choice Labs

An option is to use the typical 4in1 test kit you can buy here for about $35, plus these:
Chlorine FAS-DPD 3-in-1 Kit Clear Choice Labs for $37, and
https://clearchoicelabs.com.au/product/cya-detection-kit-small-size/ for $27

Test strips are not reliable, plus they're not accurate.

The only other reliable option is to drain the water, scrub it out with dilute bleach, towel out the remaining water, then refill. If that's a better option for you, there's a system described here: Pool School - Guide for Seasonal/Temporary Pools

As long as you're starting with city water, and not river or dam water, you'll get trouble-free pool water either way. If you're on bore water, we would need to consider iron as a contaminant. If you've put any cheap algaecides in the water, we'd have to consider copper as a possible problem.

It's easy once you get a test kit, rid the pool of algae, and follow TFPC, mostly because there's heaps of help here at TFP.

 

[michael73]

Thanks for your informative replies guys.

I'm confident the CYA is under 50, I'll maintain FC above 10 for a few days, monitor PH and sweep the pool and see how it goes, if that doesn't work I'll look into the other test kits.

I'll keep TFP updated ??

 

[cooljul]

Hows it looking michael?