Boomer..Two Carbon Quesions

[kyley]

Hey Boomer,
I switched out my media yesterday (from SeaChem SeaGel [matrix carbon & phosguard] to BRS ROX and HC GFO). I'd always tumbled a bit with the SeaGel. Since it's not recommended to tumble the carbon, I'm not now, but in order to prevent the tumbling and just have a small movement of the carbon, I have to dial down the ball valve attached to the pump so there's just a small trickle of water coming out of the reactor's 1/4" hose. I'm concerned that this way I'm not treating enough water??? A lot of the ROX grains seem to float anyway so it seems impossible to avoid some collision.

If the problem is the grains grinding together and breaking down into dust, would it make sense to have the divider sponges pushed close together (trapping the ROX - and GFO) so the grains can't really move much? Then turning up the water flow substantially higher? Seems a lot of trade-offs here! I felt like I could treat more water with higher flow with the SeaGel. Thanks again for your advice,
--Kyle

 

[Edward Smith]

I found this summary of UV destroyers: http://www.spartanwatertreatment.com/UV-ozone-destruction.html

The Coralife Turbo Twist appears to have the correct wavelength. I think (?) the next question is how much contact time does the water need to have with the light in order to remove residual ozone?

I was intending on running the ozone treated water at about 90g/hr, Tee'd into the UV filter intake. The UV runs at 680 g/h, so....the ozone treated water will be running past the bulb at 650 g/h.

Do you think that will be adequate time to break down the residue ozone? I could always slow down the UV intake speed?
Any obvious flaws in this plan?

Thanks,

 

[Boomer]

Nope, it has the wrong range of UV for a Ozone Destructor Even if it did it would be about useless as your water has Bromide and the half life of Ozone is only a few seconds in the presence of Bromide. It is not the Ozone in a system it is the Hypooborus acid created for the reaction of Ozone with Bromide. If you measured the Ozone, with a TRUE Ozone test kit you would find about none but there would be lots of Hypo there.

 

[DeathWish302]

Hey Boomer,
I switched out my media yesterday (from SeaChem SeaGel [matrix carbon & phosguard] to BRS ROX and HC GFO). I'd always tumbled a bit with the SeaGel. Since it's not recommended to tumble the carbon, I'm not now, but in order to prevent the tumbling and just have a small movement of the carbon, I have to dial down the ball valve attached to the pump so there's just a small trickle of water coming out of the reactor's 1/4" hose. I'm concerned that this way I'm not treating enough water??? A lot of the ROX grains seem to float anyway so it seems impossible to avoid some collision.

If the problem is the grains grinding together and breaking down into dust, would it make sense to have the divider sponges pushed close together (trapping the ROX - and GFO) so the grains can't really move much? Then turning up the water flow substantially higher? Seems a lot of trade-offs here! I felt like I could treat more water with higher flow with the SeaGel. Thanks again for your advice,
--Kyle

I'll let master Boomer chime in, but here goes:

1) Tumbling creates dust and has the same result as channeling in other media like DI resin. You basically have a large qty of water pass around the GAC instead of through the media.

2) The lower the flow, the better the absorption action. Think about running your RO system at 2000gph. Do you think you would have a 98% rejection rate....not a chance.

A tight carbon pack + slow flow = most efficient use of GAC.

 

[Boomer]

I agree DW but no too "tight packed"

The lower the flow, the better the absorption action.

But no to slow either Water pressure helps drive things into the GAC just like higher RO pressure = higher rejection rate.

Any filtration units have what is called "Break Through Flow Point". Some filers can go way beyond their BTFP and still be effective but others can not exceed it. A good analogy is a hanging box filter vs a Ehiem base feed canister filter.

Ehiem

Hagen Box

The Ehiem 2015, for 100 gal tank, is 620 l /hr and that is about its BTFP. It can run up to say 200 -400 % its BTFP and still be very efficient.

Now, that box filter, a Hagen Model 10 for a 100gal tank, is 630 - 1800 l / hr but its BTFP is more like say 150 l / hr at 100%. So, that unit is pushing waaayy to much water. That the water just goes around the media, either over it or under it.

Filter cartridges, like those for DI or similar have BTFP in between these two. A reactor is in between the cartridge and the box.

Do I know what the flow rate should be for a reactor ? No, one would need to run extensive tests, so it best to run them according to the manufacture or slower, so there is NO tumbling just the GAC kinda moving and barely moving, as if it is vibrating a wee tad.

 

[kyley]

DW302, Boomer, thanks for your thoughts on this. Unfortunately slow flow and too slow flow are all relative and hard to "see" (I don't have anything to compare to). So I'm going to measure the flow through my reactor soon and see what it's actually running at; now that it seems very slow to me I'll let you know when I've done that. Thanks again,
--Kyle

 

[DeathWish302]

I just love how Boomer takes what I have turning in my head and beautifully moves it to forum posts..... That's exactly what my tech head had churning, but typed a whole bunch of garble....

Thanks Boomer! :beer:

 

[las]

Is ROX STILL THE BEST gac out there?

 

[bertoni]

I don't know of any new data in this area, or much in the way of new products. The ROX 0.8 does get good reviews.

 

[las]

just bought some rox... is the slow flow rule still the best way to run it in a reactor?

 

[bertoni]

Yes, I'd be careful not to grind it up.

 

[las]

Yes, I'd be careful not to grind it up.

Is this because grinding it up creates more of a chance for HLLE to occur in my fishes? Any other reasons for not using a tumbling motion?

 

[bertoni]

HLLE is one possibility. I don't think we know all the possible side effects of carbon dust, though, and I suspect it's not going to be helpful for filtration if it stays in the tank.