Brightwell Phosphate - E Update and Info

Badboyan93l · Aug 29, 2023

Hi Randy,

I hope all is well. We spoke last week regarding the Phos levels dropping from 0.9 to .06 in one day. I skip two days and re-dosed and phos dropped from 0.67 to 0.44, and kept dosing half of the full dose everyday after until I start to see the level drop just slightly, it no longer dropped by 1 or 2 ppm daily. Instead, it'll drop by .05 or so. Now, two days ago the levels were 0.32 so I dosed the full amount 25 ML and it slightly dropped to 0.27 as per yesterday's hanna readings. I went ahead and dosed another 25 ML yesterday and today the readings came back to 0.28. I wondering why is no longer dropping, is it because of the phosphate that are in the rocks and sand bed as per previous discussion?

Thanks,

Angel

Randy Holmes-Farley · Aug 29, 2023

I’m not sure why it would be getting harder to lower it unless you are also waiting longer between dosing and measuring

jda · Aug 29, 2023

The rock and sand with higher concentrations might be in harder to access places and it takes more time for the phosphate to unbind into the water column. It is like the easy stuff unbound already. If it took months of years for deeper parts of the sand or inner parts of the rocks to bind, then it will take longer for it to unbind too.

You can get po4 down to nothing with Lan Chloride, but the lower you get, the more days that you have to wait until you can dose again. I do this with rock that I get from broken down tanks where i can get the po4 level in the bin down to like .05 pmm in the same time that I can get it from .05 ppm to 0-1 ppb on a Hannah.

Badboyan93l · Aug 30, 2023

jda said:
The rock and sand with higher concentrations might be in harder to access places and it takes more time for the phosphate to unbind into the water column. It is like the easy stuff unbound already. If it took months of years for deeper parts of the sand or inner parts of the rocks to bind, then it will take longer for it to unbind too.

You can get po4 down to nothing with Lan Chloride, but the lower you get, the more days that you have to wait until you can dose again. I do this with rock that I get from broken down tanks where i can get the po4 level in the bin down to like .05 pmm in the same time that I can get it from .05 ppm to 0-1 ppb on a Hannah.

Good to know. Thanks Jda