best powerhead for salt mixing tank....

[ReefEnabler]

My tank system uses a 50 gallon water changing tank, so I change up 50g at a time. The WC tank has both an RODI topoff float valve, and a drainage bulkhead on the bottom. Once it fills up, I add salt, and then just open a valve and my tank water circulates through the mix tank, and overflows back to the sump.

Overall this design has worked out very well for me, it's much easier than manual waterchanges where you need to turn off the return pump etc....

But there is one part of the process thats much more of a PITA than I anticipated...... adding the SALT to 50G of water. It's a ton of salt to add all at once, so I try and only add a few cups at a time. Even so I end up with a mass of precipitation and the water stays cloudy for about 2 full days. I had to scrape a thick white film off of everything in the tank since I didn't want all that calcium cabonate buildup going into the equipment in my sump.....

I am currently using a Hydor Koralia 4 to mix, which is rated at 1200gph. It's OK, but still alot of salt falls to the bottom of the tank unless I add the salt REALLY slow, like slower than I have patience for


I am thinking that if there was alot more flow in there, there would be alot less precipitation.
I read about somebody using a prop on a drill to really agitate the water, but I think I'd still need a few hours at least with a 50g mixing tank.... so probably not the most feasible idea on that scale.


So what's the most flow I can get out of a powerhead for the cost? Obviously not wanting to pay for an expensive tunze just to mix the salt....

So far the Koralia Magnum 8 is the best I can find, its rated at 3200 gph, and costs ~170 at MD http://www.marinedepot.com/ps_ViewIt...ry~FIPHFF.html


Anything else I should consider? Looking purely for GPH per $$$
The Magnum8 looks like around 5.2 cents per 1gph

[nauticac4]

I am using a sureflow modded MJ 1200 in a 25 gallon brute trashcan. I dump a cup at a time in as I am measuring and I dont seem to be having the problems you are. I am using the white prop that comes in the sureflow kit. marine depot was having a sale on these a couple weeks ago. give 2 of them a shot.

[nauticac4]

BTW that is .007 cents if you get the mods and all for 60 bucks shipped.

What kind of salt are you using I am using seachem Reef

[ReefEnabler]

Thanks nauticac.... kinda forgot about those sureflow mods!

So MD claims that a modded MP1200 will get about 2000gph... not bad! considering the stock MP1200 is only 295gph....... does it really get those kind of increases???



I am using Coralife salt.

[Mr James]

Yes it does Ryan. I put a modded MJ1200 on my 58g reef and it was too much. So I replaced the 1200 with a 400 and that is plenty!!

I mix salt in a 44g Brute with a Mag 9.5, which also serves as a back up for other misc. pumps.

[pjf]

A heater will help dissolve the salt quickly.

I don't mix more than 20 or 30 gallons at a time but all I use is a heater and a powerhead. My powerhead is a plain MJ-1200 mounted on a Sure-Grip 50 magnet. I use two heaters for a total of 500-watts: an Eheim Jager 200-watt and a Finnex titanium 300-watt whose thermostat I no longer trust.

I'm planning to upgrade my MJ-1200 with a propeller mod and will continue to use heaters that have failed ON as my salt mixing heaters.

[Mr James]

I used to use a heater too... but just stopped I guess. But I do aerate the water with an air pump.

[mfinn]

I use mag 9.5's in my 44 gallon containers

[customcolor]

here is a 1560gph that is cheap for its gph and its not a wide flow (which i think is part of the problem)
pump
i think you could just set that pump on the bottom of the mixing container you use and it will mix any thing down there fast! plus shooting at that speed it will cause some great movement of water when it hits the side of the container and through all the salt up in to the water to help the desolving of it.

i use 2 400gph pumps in an old 55 and it works fine to mix in 24 hours. plus i put them angled down to mix up what sinks.

[Indymann99]

Mag 9.5 in a 32g Brute. I also have a airstone and heater. The Mag 9.5 is on a timer to run 15min every 2 hrs. I usually age water for approx 1 week.

[jmccomb420]

When I was working at a lfs we used rio 32 pumps in our 32/50 gallon brutes with no problem. started with a little hot water (about 4 gallons) added salt and started pump then topped off with cold (we were using tap water though). Even so I made plenty of buckets with straight cold with no issues so the RO should work at room temp.

[SasquatchFarmer]

Well I am setting up a new aquarium that doesn't yet have a heater, and was going to do a nearly 100% water change. I was mixing up about 40 gallons in my 44 gallon Brute. I had some extra koralia 4's sitting around and just put 2 or three of them in the brute, all pointed so as to make the water circulate round in the same direction. Worked great, all the salt dissolved in maybe 30 minutes. I did mix the salt in slowly though.

I previously mixed salt in a 20 gallon AGA with a mag 7 and a quiet one 3000. that also went very well, but instead of a white scum, I had a brown scum. I was using instant ocean then and also now in my brute. I didn't get the brown scum when I mixed in my brute as described above, but I think adding the salt slowly got rid of the scum problem (before I added a bunch fast).

Sorry for rambling, I would use koralias or better yet mj mods.

[ReefEnabler]

thanks for the suggestions guys, I got two MJ 1200s with the sureflow 1600 mod and the flow it puts out is impressive!

definitely mixed alot better than the koralia 4.

[jdieck]

For a 50 gal mixing tank a mag 9.5 and three or four airstones work very well.
My setup is a 55 gal tank and uses a 9.5 mag for mixing and transfering water, the mixing system has two valves when one is closed and the other open, the water from the pump recirculates back into the bottom of the tank were two hoses on a T make the water swirl around. Three airstones create a lot of additional agitation that I get total dissolution in 10 to 20 minutes. The air also serves to carry in CO2 from the surounding air to stabilize the buffers in the salt mix.
I also added two 350 watt heaters to equalize temperature before the water change.
To change water just open the drain valve on the sump, close the recirculation valve and open the transfer valve on the mix tank.

[Garage1217]

I use a mag 7, also acts as a heater in my 5G bucket hahaha.

[sjm817]

Originally posted by RyanBrucks
My tank system uses a 50 gallon water changing tank, so I change up 50g at a time. The WC tank has both an RODI topoff float valve, and a drainage bulkhead on the bottom. Once it fills up, I add salt, and then just open a valve and my tank water circulates through the mix tank, and overflows back to the sump.

I'm a bit confused on the setup. You dont mix the salt before doing a water change? You circulate the tank water through the SW change tank? the salt should be fully mixed before doing a change. I mix for a minimum of 24 hr. I also dont follow the reason for circulating tank water through the mixing tank. Also, you should not have stuff precipitating out of your salt mix. What are you using?

[GSMguy]

i think he mixes the salt then opens the valve scott.

[sjm817]

Yeah, I need clarification of the setup. I'm thick and need things spelled out plainly . Mixed for how long? I still dont get the precipitation issue. That should not happen.

[GSMguy]

ya the precipitation has me stumped too, no reason it should precipitate.

[jdieck]

Assuming he is using RO/DI then we can discard precipitation due to initial alkalinity in the tap water. Also we shall assume that the water is indeed mixed but as he mentions there is not enough agitation.
WHen there is not enough agitation in the bottom of the tank, the added salt just piles up in the bottom. When the salt starts dissolving the buffers are very concentrated so there is a very high PH concentration within the salt/water interface and the calcium and alkalinity precipitate into calcium carbonate as soon as the buffers start dissolving.

The issue here is that he is using the amount of flow to judge the pump perfomrance, in this case what is needed is agitation which comes from flow velocity not total flow.
Although propeller powerheads have a larger flow, their velocity lower that the velocity to be obtained from a traditional overhed. In addition a Koralia for that volume of water is way undersized.

For effectiveness the idea here will be to maintain the salt particles in suspension until dissolved. To do so a good powerhead should be either pointed stright down to the center bottom of the container, another posibility is to use airstones in the bottom to create uplifting.
Of course the higher the velocity of the flow (the more powerful the powerhead) the bigger the agitation.

[ReefEnabler]

not sure what happened with the precipitation last time, but as Jdiekc said I suspected lack of agitation (mixing power).

anyways 2 Sureflow mods kept the salt in suspension the whole time, didnt even let any touch the bottom so that must be why there was no precipitate. I have them angled at the ground.

I must have just added too much salt too quickly last time, compared to the relatively low flow the tank used to have.


Sjm817,

Here's the basic overview of how my mixing/waterchange tank works:

I fill it with RODI water, then I add salt and turn on my mixing powerheads. After a day or too, when I judge that the salt has mixed for long enough, then I open a valve, and this valve allows water from my SUMP to be pumped INTO the mixing tank. My sump water is pumped up through a 1/2" pvc pipe from the return pump positioned all the way at the bottom of the mixing tank, and the valve controls it.

So when my system water is added, it causes the tank to overflow, and there is an overflow drain that goes back to the sump. So basically it adds sump water until it overflows, and slowly mixes my system water with the new water.

This lets to use the valve to mix the new water as quickly, or slowly as I want. If I open the valve barely, then system water will just trickle in, and it will take hours if not days for all the water to mix (new and old water), if I open the valve alot more then it all happens much faster.

Whenever I am ready to do another water change, I isolate the mixing tank again (close off the valve feeding and draining it), and then open a valve on the bottom of the tank, which completely drains it to the waste drain. By that time it will be very mixed with the rest of my water.

Then I just refill it with RODI water (by opening a ballvalve before the Float valve).

The idea was to make a water changing tank that allowed me to change water without shutting down the main return pump or interfering with the main tank at all.

Yes there is a decrease in efficiency this way, but its only a 2% decrease, because every time I empty the mixing tank, I am taking some of the good water. I posted the exact detalis of that in my thread a long time ago I'll dig it up.


Hope that helps clarify.

[ReefEnabler]

"Its a 2% reduction in efficiency to do it that way, but IMO the benefits far outweigh the negatives. Its roughly a 13% water change, whereas a normal 50g water change would be a 15% with my volumes.

Basically, in between water changes the mixing tank is an actively circulated tank just like the fuge or frag tank. Thats why its a slight reduction in efficiency, its adding to system volume but I'm still only changing 50g. "

[ReefEnabler]

the tank right above the sump is the Mixing tank:



You can see the Sureflow MJs and the Koralia 4 (actually going to replace that with a heater soon). The PVC right in-between the powerheads is the 1/2" line from the return pump.

Also if you look to the left of the mixing tank, if you see an orange valve in the closed position, that is the valve that controls the oveflow drain (so the sump). I close that off just to make sure RODI water or un-mixed saltwater doesn't make its way to the sump.

Behind the Skimmer, you can see Three 1" pipes going to the sump. One of these is the Refugium (top left tank), the other is the frag tank (middle left), and the third is where the mixing tank drains to the sump.

hope that clears it up. Thanks for the suggestions everybody I hope somebody else learned something.

[leoslizards]

I use a Koralia 3 in a 10g mixing tank pointed towards the bottom.

Btw, nice setup Ryan. I might have to borrow that idea from you when I upgrade to a sump/fug. What's that small tank next to the laptop, controller, switches, etc... ?

[rj ripetide]

Ryan Brucks.... That's one impressive set-up!
I am looking to re-plumb my basement sump, refugium, and frag tank. I like the idea of the mixing tank.
Would you please give me some more details of how you have the whole set plumbed?
What type of controller are you using? I see your LT keyboard and what looks like a controller next to it.
Thanks for any help you can give me for my project.
Rj