Nilsen Reactor

[MiNdErAsR]

So if Jeff's case of evaporating 7-8 gallons/day, you can easily see the need for a wide and tall reaction chamber.

Correct me if I'm wrong, but aren't these Nilsen's (I've seen Ecotech's but not MyReef's) RO/DI fed via litermeter or similar? If so, then diameter nor height of chamber would matter because if the unit held 3 gallons or 10 gallons and your evap rate was 3 gpd or 20 gpd there would always be enough. The kalk settles to the bottom and you never drain the unit entirely and the litermeter would maintain the water level within the reactor.

On another note...Nilsen's aren't the be all end all of maintaining alk/Ca. Sooner or later your tank's calcium demand will outgrow the limits of kalkwasser. At that point a calcium reactor would be very handy. However CO2 impact on the tank would be minimal as the Nilsen would handle the bulk of the load (theoretically). This is the route I plan to travel. My Ecotech is on order!

Great thread guys.

 

[SPC]

Posted by MiNdErAsR:
Correct me if I'm wrong, but aren't these Nilsen's (I've seen Ecotech's but not MyReef's) RO/DI fed via litermeter or similar? If so, then diameter nor height of chamber would matter because if the unit held 3 gallons or 10 gallons and your evap rate was 3 gpd or 20 gpd there would always be enough. The kalk settles to the bottom and you never drain the unit entirely and the litermeter would maintain the water level within the reactor.

-I agree and also wonder if one stirring (or shake :wink: ) per day wouldn't be enough to keep the lime water at full saturation.
Steve

 

[danmhippo]

Steve, I look forward to your 5 times daily testing of Kalk reactor effluent report! 8)

 

[Anonymous]

Posted by MiNdErAsR:
Correct me if I'm wrong, but aren't these Nilsen's (I've seen Ecotech's but not MyReef's) RO/DI fed via litermeter or similar? If so, then diameter nor height of chamber would matter because if the unit held 3 gallons or 10 gallons and your evap rate was 3 gpd or 20 gpd there would always be enough.

The taller unit has a couple of advantages

1. you can dump more of the Kalk powder in it. If you dump 3" of kalk powder in a 10" reactor then you only have 7" of the clear Kalk. Also with the smaller reactor more of teh clear kalk will bge disturbed during mixing.

2. As you add RO/DI water to the reactor you are diluting the clear kalk until you mix again. the larger reactor will dilute less.

 

[Anonymous]

If so, then diameter nor height of chamber would matter because if the unit held 3 gallons or 10 gallons and your evap rate was 3 gpd or 20 gpd there would always be enough. The kalk settles to the bottom and you never drain the unit entirely and the litermeter would maintain the water level within the reactor.

On another note...Nilsen's aren't the be all end all of maintaining alk/Ca. Sooner or later your tank's calcium demand will outgrow the limits of kalkwasser. At that point a calcium reactor would be very handy. However CO2 impact on the tank would be minimal as the Nilsen would handle the bulk of the load (theoretically).

I would think that a 3 gallon reactor trying to handle a 20GPD evaporation rate (depending on the frequency on stirring) would be dispensing less than saturated kalk at some point. From everything I read before I built mine, you want to keep the mixing in the bottom third of the chamber. Having a smaller chamber, you would would have to add less kalk, and therefore would have to add kalk more frequently to the reactor, which kind of defeats of having one (I like to be lazy ).

I have never though that Nilsen's were the end all of maintaining alk/CA. It partly depends on tanks calcium needs. I could not justify the expense of a Calcium reactor for my 55 with what I am keeping (a mixute of sofites, LPS, SPS, clams) and the Nilsen has provided everything I have needed for the past 2 years. But on the 180 I am setting up(which will be an SPS/Clam tank), I will be doing the same, adding both a Ca reactor and Nilsen.

 

[Osama]

For my 180G reef tank; I started with a small (rated at 300G) calcium reactor within few months I added a doser to dose B-IONIC. Then I started to drip kalk. Now two years and a heavily stocked tank with my calcium level & Alk down; I added a LARGE Nielsen & a large calcium reactor. Hoping this will be plenty good for my inhabitants & will be capable of supporting a larger tank in the future.. Hopefully not too distant future... Lessons learned ; capacity advertised falls short of your actual tank needs. Buy the bigger units you can afford you maybe money ahead in the long run

 

[MiNdErAsR]

Just a follow-up...

Obviously a 20gpd evaporation rate was an extreme example, and I don't know of any 10" tall Nilsen reactors. I believe Ecotech recommends multiple mixings per day, so topping off with RO/DI (litermeter) will only slightly reduce clear-kalk potency and then only temporarily. People I know with DIY Nilsen reactors tend to spin up the mix until the milky kalk just reaches the reactor effluent pump, then allow it to settle out before continuing to dose. That said, I would think a Nilsen reactor which is (for example) 3' tall and 8" in diameter would show no real benefit (besides greater volume) over the same 3' tall unit with a 6" diameter. However the difference in price would be great. Since every reefkeeper I know is looking for a bargain...well, you know where this is going.

As I originally stated, an Ecotech (which I believe is 3'x6") is handling a system near 600g without problem. Is the added expense of 8" diameter tubing worth it? Only if your system volume is significantly greater then the average home aquarium.

IMO

 

[Anonymous]

I stand corrected on the 10" reaction chamber, but the reactor on the myreefcreations.com website has an 18" reactor chamber with a 6" tube (unit stands 23" tall).

so if my calculations are correct gallonage for a cylinder is pi*r*r*h/231

so an 8" would be 4*4*3.14*18/231 = 3.9 gallon

a 6" would be 3*3*3.14*18/231 = 2.2 gallon

this would give you an additional 1.7 gallons

ecotechmarine.com didn't give any specifications for thier reactor so I can't comment on them.

however I think we both would agree that it would be better to add height rather then the larger diameter.

 

[SPC]

Posted by JDM:
2. As you add RO/DI water to the reactor you are diluting the clear kalk until you mix again. the larger reactor will dilute less.

-Someone help me out here with this assumption. The RO/DI water for my reactor is released in the bottom 1/4 of the reactor. On the bottom of the reactor sits kalk mix with a certain % viable and a certain % not. As the RO/DI water enters is it not somewhat effected by the kalk that is just laying on the bottom? IMO this RO/DI water is not just diluting the lime water but instead is being saturated to some extent by the bottom layer of kalk mix.
Steve

 

[Anonymous]

I would agree that the kalk on the bottom "somewhat" effects the input RO/DI water but not to the point of saturation. I would think that is part of the reason for the periodatical stirring of the mixture (to ensure the viable kalk is kept at a maximum saturation).

also isn't the density of the input water less than that of the kalk water? this would cause the input water to rise to the top not settle down with the powder. At least this is my illogical thinking. please correct me if I'm wrong!!

Oh, another reason for a larger diameter would be greater stability. I wouldn't want a 8' tall reactor that is only 3" in diameter. to me this would tend to tip too easily.

 

[MiNdErAsR]

however I think we both would agree that it would be better to add height rather then the larger diameter.

Absolutely.

 

[SPC]

Posted by JDM:
I would agree that the kalk on the bottom "somewhat" effects the input RO/DI water but not to the point of saturation. I would think that is part of the reason for the periodatical stirring of the mixture (to ensure the viable kalk is kept at a maximum saturation).

-I agree that this is the reason for the stirring, my question is does anyone really know how much stirring is needed? If it is only once/day (which it just might be) then maybe it would be just as easy for some to just give the reactor a good shake and not even employ a mixer of any kind.
Steve

 

[Anonymous]

If the top 3/4 of your reactor held your daily evaporation (since the water is coming in the bottom 1/4) and the density of the saturated kalk stayed on top of the RO added (??), I would think only a once a day mixing would be fine. I doubt however the second would be true.

 

[Osama]

Was wondereing if I should start a new post on this next 60 questions: I had a small single chamber calc reactor going for 2 years: effluent today=pH6.6;dKH>32;Calc=560.
10 days ago added new large dual chamber calcium ractor & Nielsen (8" diam); effluent from second chamber of calcium reactor= pH=7.1; dKh>32; Calc=560. I think the above reactors are working fine ... Do you agree???
the effluent from the Nielsen is pH=11.95; dKh>32; calcium=360. calcium from Nielsen reactor is low. do you agree.?
Tank parameter: ph=8.3, Alk=6.4 dKh ; calc=410
OK here goes; effluent from all 3 reactors are VG for Alk (>32dKh) SO I assume that with time my tank Alk will get higher & be OK. I will give it 2 weeks & see. Do you agree?
How about my calcium level from the Nielsen is low and I put out more effluent from my Nielsen so I am afraid that my calium levels in the tank will dop.
My question: what do you think about the values I got AND how can I increase the calcium output from the Nielsen......
Effluent rate from Nielsen=3Lper day using Liter Meter doser
effluent rate from calcium reactor at 40DPM for each of the two calcium reactors.
Temp= 80 degress; ORP=420
Should I add an Alk buffer & then let the reactors maitain things

 

[john f]

Why do you think 360ppm is low for the Nielsen?
Remember if you didn't add Kalk you would be adding RO water for evaporation with zero ppm calcium. You now have 360ppm more per gallon of replacement water.
Remember also that your calcium reactor gets to take seawater at 410ppm to start with, and bumps it up to only 560ppm. So the calcium reactor only adds 150ppm while the Nielsen adds 360ppm. Now the calcium reactor can do this all day long without regard to evaporation rate, so it will add more net caclium and alk to the system.
But I'm not too sure you can get alot more calcium out of kalkwasser anyhow.


John

 

[Osama]

John; you make a very good point about the Nielsen putting out 360ppm calcium starting with RO water. THANKS.
So are my outputs reasonable or should I expect better effluent? and
How long will it be before my 220 g system reaches a dKh=12-13 ? How can I calculate that?

 

[MiNdErAsR]

Tank parameter: ph=8.3, Alk=6.4 dKh ; calc=410

Just a thought. Are these parameters maintained? In other words they don't change (except pH)? Normally calcium reactors are set to maintain levels once they are achieved via other means. If the above posted readings are stable, I would add some sort of buffer to bump up the alkalinity to your target level. Then without changing reactor settings that level should be maintained without problem.

 

[Osama]

Jim; My system was stable when I dosed 7/24 B Ionic. I am hoping with all three reators that I can get by without the BIonic. My system is heavily stocked.
Are the effluent as good as can be expected? AND
by increasing the rip rate on the calcim reactors will I be able to bring up the dKh to 12 from 6 &
the calcium slightly from 410 to 430.
Can this be calculated; as to what drip rate I should tune the reactors to?
My experience with reactors is limited to my samll calcium reactor that I just let run & added BIonics ...

 

[MiNdErAsR]

The numbers look ok, but using drips to measure effluent flow rate doesn't help me. It's much easier if you actually measure ml/min. That said, I would try to increase the effluent flow rate without changing CO2 feed...yet. Increasing effluent from (for example) 30ml/min to 40 or 50 ml/min will increase effluent pH. It also *may* increase tank alkalinity. If tank alkalinity drops then increase CO2 feed slightly. Monitor effluent pH during this procedure, as you don't want the pH from the first chamber to drop below 6.50. In my case 6.50 pH from the first chamber means 6.70 pH from the second. YMMV. Also allow 24 hours between reactor tweaks for things to settle into place. Measure tank alk before and after, and log everything (effluent flow rate and pH, tank alk, etc.). Watching the trend makes dialing in the reactor a snap. It's just time consuming because of the lag between setting adjustments and resulting changes.

The problem is every system is different. By that I mean reactor settings, calcium demands, etc. So even if we had the same reactor on the same sized tank, our settings could be miles apart. In my case I have to drive the reactor (K2R with added second chamber) with an extremely high effluent flow rate (300ml/min). However my effluent is 6.80 pH and that maintains ~11 dKH in my 120g system. I know others with larger systems running MUCH less flow from the reactor and maintaining high dKH.

I hope this all makes sense.

 

[Osama]

Jim; THANKS. What you wrote makes sense. Patience is what I lack ....Thanks for the input