How to set proper time for Air Injection after backwash

[MrMechanic]

10x54 Clack tank, 2510 Fleck head, ozone mini generator hooked to air inlet, Garnet bottom, 1.5 cubic ft Filox.

I have all the flow you would ever need for backwash (can do up to 16gpm with a 3/4 drain). Currently doing a 14 minute backwash, 40 minute air injection, 2 min rapid rinse....

I have no idea how to judge air injection time, up or down...any advice would be great thanks.

A little background:
Just rebuilt the head unit (new to me house, tank was leaking 24/7 out drain...it was all gunked up not working one bit).... emptied the tank, washed and refilled...also made my basket slots just a hair bigger as I had read Filox really likes to be backwashed hard. (to be safe I then put a clear spin down mesh filter post tank before water softener just to make sure I'm not blowing media through....)

Again, what is the proper "air time" calc?

Great knowledge on this board, thanks in advance!

 

[Bannerman]

also made my basket slots just a hair bigger as I had read Filox really likes to be backwashed hard.

It is not the basket slots that influence the backwash rate, it is both the DLFC (drain line flow control) restrictor and water temperature that does.

Although you specified the backwash and other settings, you did not state the DLFC rate. Depending on what the prior media was, the DLFC restrictor may need to be replaced.

What is the output rate of your Mini Ozone Generator?

 

[Sponsor]

 

[ditttohead]

Air injection time is typically not critical... 40 minutes is common but it also depends on your injector size. Frequency of backwash is important.

Did you take any pictures of the gunked up valve? Please post if them if you did.

 

[MrMechanic]

It is not the basket slots that influence the backwash rate, it is both the DLFC (drain line flow control) restrictor and water temperature that does.

Although you specified the backwash and other settings, you did not state the DLFC rate. Depending on what the prior media was, the DLFC restrictor may need to be replaced.

What is the output rate of your Mini Ozone Generator?

First thank you for the reply, stumbled across this forum and it seems to be great for a DIYer.

I did order a new DLFC restrictor (set for a 10x54 tank and Filox, gets here later this week). When I removed my basket and cleaned the whole thing I then tested it's gpm and it was weak...maybe 6...that is when I slightly modified it and it could push 13. I figure the DLFC might be the design control but your basket can be a limiting factor if I understand the system...does this make sense?

I'm not quite sure of the mini ozone gen output, here is a pic...pretty small unit.

I am getting plenty of air out of the drain line during air fill....can you put too much in the tank...that is what I'm worried about?

Additional note, the very start of backwash is quite severe on the drain (the escaping air brutally escapes)....I'm guessing this is normal and I just need to make sure the drain lines are tied down well?

 

[MrMechanic]

Air injection time is typically not critical... 40 minutes is common but it also depends on your injector size. Frequency of backwash is important.

Did you take any pictures of the gunked up valve? Please post if them if you did.

Thanks for the reply!

The only pic I took was just for laughs during rebuild. I cleaned up all the orfices and such, and the vacuum on the air line now during air intake is quite good in my opinion.

My worry is I'm over filling my tank with air or is this not possible?

Just my wife and I and one kiddo. I'm doing a nightly backwash except when we're on vacation (have a diy home automation system to control just about everything including outlets...save that for another story)

Additional notes, this tank is setup prior to a Hague watermax softener system (from previous owner). Also a pic of my bowl post filox resin tank, pre softener (just to ensure my diy basket upgrade isn't letting too much filox through....so far besides the initial small pieces it seems to be good).....

Again real question is just trying to understand air intake timing and the logic behind knowing how much water is being displaced by air....was thinking I could run water through the system and then use my IR gun to see if I can see the heat sig difference between the air pocket and the water line....thoughts?

 

[ditttohead]

Air compresses, water doesn't. So even if you displaced the entire tank with air, it would still be fine. I have doe it for years with a clear tank for testing purposes, 40 minutes with a #1 injector on a 10x54 tank seemed fine. a little less time, a little more time, never appeared to critical. Since the air injection is based on venturi injection, you are still introducing water during the entire air draw time.