Ca reactor stops dripping... How come?

[tgunn]

Hey all,
I've been attempting to tune a Ca reactor I bought off a local reefer..


I am feeding it with an aqualifter pump and controlling the effluent drip rate using a small PVC gate valve (sorta like a needle valve). Feed and effluent lines are 1/4" RO line.

I am able to adjust the drip rate "just right" but invariably after a number of hours it slows down and completely stops. If I open up the valve just a tiny bit it starts dripping again and then slows down or stops.

Am I missing something here? Why does this thing seem to slow down dripping all the time?

I'm finding it almost impossible to get the right amount of effluent and even more difficult to get the right bubble count. I've got a pH controller coming in the next week or so to help me get the pH of the effluent correct, but I can't seem to stabilize the dripping.

Any ideas GREATLY appreciated. Oh, and in advance, NO, I will NOT get a dosing pump. That's 100% out of the question at this point in time.

Thanks,
Tyler


I've managed to get it to drip at a constant rate

[Malifluous]

your getting precipitation in your valve thats clogging it

[tgunn]

Originally posted by Malifluous
your getting precipitation in your valve thats clogging it

I was always under the assumption that the low pH of the effluent would help prevent this in combination with the backpressure in the reactor from the feed pump..

Is there any better way to set this drip rate? Or will the problem go away on it's own? I can't see that putting the valve on the INPUT side of the reactor will help, will it?

Tyler

[Malifluous]

Your assumption is correct. Perhaps a better valve would work. the needle valves always clog. Hopefully someone with a Ca reactor can give u better advice. I have the same problem using limewater.

[manderx]

i've never had an outlet valve clog with calcium. though i have had the outlet tube clog with algae over time before i switched to a black tube.

my bet is the aqualifter just doesn't have the oomph to supply steady pressure. i like to tee off my return pump. seems more consistent plus it's a bit more pressure, which as long as the reactor is well made and can take a little pressure, helps the co2 dissolve better. also one less device to plug in.

[tgunn]

Originally posted by Malifluous
Your assumption is correct. Perhaps a better valve would work. the needle valves always clog. Hopefully someone with a Ca reactor can give u better advice. I have the same problem using limewater.

Catch-22, a JG Ballvalve plugged quickly too and I could not adjust the drip rate accurately enough..

hmmm.

[tgunn]

Originally posted by manderx
i've never had an outlet valve clog with calcium. though i have had the outlet tube clog with algae over time before i switched to a black tube.

my bet is the aqualifter just doesn't have the oomph to supply steady pressure. i like to tee off my return pump. seems more consistent plus it's a bit more pressure, which as long as the reactor is well made and can take a little pressure, helps the co2 dissolve better. also one less device to plug in.

Hmm, I originally was feeding the reactor with a MaxiJet 1200 and ran into the exact same problem...

I will have to talk to the builder of the reactor and see if it can handle the pressure from my return pump... I'm running a PCX-70 which is a pretty hefty return pump and it pushes the water all the way upstairs, so it's fighting against a fair amount of head pressure....

Thanks,
Tyler

[manderx]

yeah, that return pump will probably be too much with all that backpressure. you could use a pair of valves on the inlet to reduce pressure, first one barely cracked the then second one split off a tee to drip back in the sump to reduce the pressure. but if a fleck of rubble got caught in it something bad might happen.

is the valve getting clogged with precipitation, or flecks of media? looks like a big recirc pump that might be stirring things up too much without something to keep the media in place.

i've been using a JG valve for years no problem never clogging. i also use a gilmont flow meter to help set and monitor the rate, though it's a pricey little thing ~$90.

[tgunn]

Originally posted by manderx
yeah, that return pump will probably be too much with all that backpressure. you could use a pair of valves on the inlet to reduce pressure, first one barely cracked the then second one split off a tee to drip back in the sump to reduce the pressure. but if a fleck of rubble got caught in it something bad might happen.

is the valve getting clogged with precipitation, or flecks of media? looks like a big recirc pump that might be stirring things up too much without something to keep the media in place.

i've been using a JG valve for years no problem never clogging. i also use a gilmont flow meter to help set and monitor the rate, though it's a pricey little thing ~$90.

Yeah, the splits and what not off the return pump would end up complicating things a bit too much I think.

I'm not sure if the valve is getting clogged with precipitation or flecks of media. If I crank it open just a slight bit more I don't see any sign of media flecks coming out... I suppose I can take the valve off and see if anything is built up in there though.

Yeah, the recirculating pump is a bit large; it's a PCX-40.. All the tubing and fittings are definitely restricting it considerably though.. I can't see any signs of larger media chunks getting propelled up in the reactor but I suppose it's possible that fine particulate is the culprit.

The builder of the reactor suggested a dosing pump. :rolleyes1:

Thanks for the help. I'll take the valve out to see if I can determine why the valve is plugging.

Tyler

[manderx]

you can get a dosing pump off ebay for 35 bucks. i've gotten a few, and a few friends have and we've all been happy. just search on 'peristaltic'.

[Henry Bowman]

You should try regulating the flow from the inlet side of the reactor. ie. between the aqualuft pump and the reactor instead of the effluent side....? Over there, the valve may not get clogged from precipitation coming out of the reactor...

[tgunn]

Originally posted by manderx
you can get a dosing pump off ebay for 35 bucks. i've gotten a few, and a few friends have and we've all been happy. just search on 'peristaltic'.

I must be missing something; all the variable speed dosing pumps I see are going to cost a good couple of hundred bucks on eBay..

What kind are you using?

Thanks,
Tyler

[tgunn]

Originally posted by Henry Bowman
You should try regulating the flow from the inlet side of the reactor. ie. between the aqualuft pump and the reactor instead of the effluent side....? Over there, the valve may not get clogged from precipitation coming out of the reactor...

Given my current lack of success with it on the reactor output side I think I will have to give a try at regulating the drip rate on the input side.

I could stick the Aqualifter pump inlet in a foam sponge to help prevent junk from geting sucked in..

Tyler

[manderx]

i guess we all got fixed speed ones (i put relays on mine to control with my litermeter so i never think about flow rates). though i have seen the variables go for 50, just gotta get lucky. though you could make a fixed speed work if you had to. use the right tubing size to get as close as you can, then use a timer to only run co2 x hours per day plus fiddle with the ph.

[tgunn]

Originally posted by manderx
i guess we all got fixed speed ones (i put relays on mine to control with my litermeter so i never think about flow rates). though i have seen the variables go for 50, just gotta get lucky. though you could make a fixed speed work if you had to. use the right tubing size to get as close as you can, then use a timer to only run co2 x hours per day plus fiddle with the ph.

The LFS has refurbished Masterflex variable speed ones but they're something like $300 or more..

It's funny what this hobby does to you; the last time I was in a hospital I saw IV dosers in a new light.

Tyler

[manderx]

Given my current lack of success with it on the reactor output side I think I will have to give a try at regulating the drip rate on the input side.

i personally think you gotta have at least some pressure on the reactor to get co2 to dissolve well. the schuran reactors run with valves on the inlet, which is why they are always full of co2 bubbles, which is the whole reason they need those complicated bubble separators on top and the venturi rather than just chopping bubbles with the pump. just a whole mess of 'features' that are only there to fix a base design flaw. pressurize the body just a little and all those co2 bubbles go away, so they don't stall the pump or escape out the effluent line.

[tgunn]

Originally posted by manderx
i personally think you gotta have at least some pressure on the reactor to get co2 to dissolve well. the schuran reactors run with valves on the inlet, which is why they are always full of co2 bubbles, which is the whole reason they need those complicated bubble separators on top and the venturi rather than just chopping bubbles with the pump. just a whole mess of 'features' that are only there to fix a base design flaw. pressurize the body just a little and all those co2 bubbles go away, so they don't stall the pump or escape out the effluent line.

My reactor does have the venturi and CO2 recirculation setup, so I'm fine in that regard.

Since you're running a dosing pump do you have the output restricted to build up some back pressure?

Tyler

[manderx]

i'm running off my return pump (velocity t2). i use the dosing pumps to dose random additives whenever needed.

[manderx]

what about gravity feeding off your tank drain somehow?

[tgunn]

Originally posted by manderx

i'm running off my return pump (velocity t2). i use the dosing pumps to dose random additives whenever needed.
what about gravity feeding off your tank drain somehow?

Yeah, I dunno. I think feeding from my overflow would be a disaster when I feed cyclopeeze and other small foods.

I am going to have to ask the guy I got it from how he was feeding it before he got a dosing pump.

There's got to be some way for this to work without one for now.

Thanks!
Tyler

[tgunn]

Well, I dunno what happened, but my Ca reactor all of a sudden decided to drip at a constant rate. OOOOOOOkay, I can live with that...