Circulation Dye Test

[mas985]

I have been wanting to do this test for some time but haven't gotten around to it until now. I ran three tests:

1) Dye in front of return at high speed

2) Dye in from of return at low speed

3) Dye in skimmer coming out of 4 returns at high speed

The only issue was that the dye faded pretty quickly from blue to green because my FC levels are currently above 5 ppm. I think the dye is meant for much lower FC levels. The videos are saved as 10x so each min represents 10 min real time. Anyway here are the results and a few comments:

Dye in front of return at high speed - Note dye change at 5 min (0.5 min video time). Full distribution less than 30 min (3 min video time).



Dye in front of return at low speed - Note dye change at 20 min (2 min video time). Full distribution less than 60 min (6 min video time).



Dye out of 4 returns at high speed - Note dye change at 5 min (0.5 min video time). Full distribution less than 10 min (1 min video time).



I might try this again in the winter when I can let FC drop.

Dye: HTH party potion at Walmart.

 

[epro05]

Very interesting experiment. It's great to get a visualization of the spread. Thanks much.

 

[jblizzle]

So would you think that only running the pump 30 minutes after adding bleach / acid on low speed is not enough then?
I mean certainly it would be better to add chems with the pump on high.

 

[mas985]

Because of the dye color change, it was really hard to tell when the dye got to the shallow end. That was my best guess but it probably occurred earlier than 60 min. But then again, high speed results seems to indicate something a little less than 30 min and I would expect low speed to be about 2x that.

 

[chem geek]

One could add chemicals slowly over each return in rough proportion to the volume of water in the area so more in the deep end than the shallow end. That way one gets most of the effect of putting it into the skimmer without sending concentrated chemicals through the pump, heater, filter.

In my pool I found that pouring over a return flow in the deep end at higher speed (48 GPM as opposed to 26 GPM for total flow rate) was mostly mixed at 10 minutes but continued to mix until 20 and was completely mixed after 30. I used FAS-DPD to measure chlorine levels for my test.

 

[JamesW]

Brushing the pool after adding chemicals speeds up the distribution quite a bit.

 

[epro05]

Now I know I'm not totally crazy because I do exactly what chemgeek said. I have 5 returns and pour some in front of each return. I must be mixing really fast, expecially if I take a swim shortly after.

 

[texasmax]

Thanks for doing and posting!

 

[WASP]

What kind of dye did you use for your tests?

Where do you buy it?

I would like to do the same kind of test for my personal entertainment.

 

[mas985]

Hth party potion at walmart.