[Tie]

What's better? I want to simply maintain Calcium and Alk without all the headaches.

I have an RO electronic auto top off system. I'm leaning to the Nielsen because they are cheaper and look like they take less space but I'm not 100% sure what the pro's and cons are.

[Ninong]

It is not a matter of which one is better. They are two entirely different animals. Most people do not bother setting up a Nilsen reactor until after they already have a calcium reactor up and running.

A Nilsen reactor is nothing more than a Kalkwasser stirrer. All you get out of it is a saturated solution of calcium hydroxide, commonly called Kalkwasser or limewater. A calcium reactor holds calcium carbonate media that is dissolved with the help of injection of carbon dioxide. You get a balanced addition of all of the elements found in aragonite, one of the crystalline forms of calcium carbonate.

The reason that people who already have calcium reactors will consider the addition of a Kalkwasser stirrer (Nilsen reactor) to their setup is because the high pH of the limewater mediates the pH lowering effect of the calcium reactor and the limewater precipitates phosphate.

A Nilsen reactor does not replace a calcium reactor, it supplements it.

[Jimbob]

Mostly agreed with what Ninong said... they supplement each other very well.


I will also state that depending on your calcium load, however, you can successfully keep your calcium and alk levels where you want them using just a Nilsen reactor (or any other drip-dosing method of Calcium Hydroxide addition). I personally do not use a calcium reactor at this point because I do not have an extra $500 lying around to get a respectable fully-functional set-up going with CO2, regulator, reactor, etc. Instead, I dose Ball's Pickling Lime (Calcium Hydroxide @ $1.49 for 450 mg) daily mixed at a ratio of one teaspoon of pickling lime to one gallon RO/DI water. In a mixed SPS/LPS/softie reef, this maintains my Ca at ~420 ppm and my Alk at ~9.8 dkH. Very low-tech, very inexpensive, but very effective.

If cost is no object for you at all and you are looking for the route that will give you consistent results with the least amount of maintenance possible, the calcium reactor would definitely be the better way to go. Just be aware that there are other successful methods out there that do not cost a small fortune.

[Ninong]

I have neither a calcium reactor nor a Nilsen reactor on my 120-gal tank. I dose Mrs. Wages Pickling Lime (limewater) nightly. Very inexpensive. My calcium stays around 450 ppm and my alk stays around 10 dKH.

If I ever get around to setting up a large tank, I will probably have both a calcium reactor and a Nilsen reactor.

[Tie]

That info helps. Thanks!

I see the benefits of the both now more clearly. I do not however have the cash to do both right now. I want to do a 250 Gal next year. I'll plan on both for dude if the project ever makes it past the finance department (my wife).

With my current 72 Gal my problem has been dosing Kalk. Because of my schedule it's hard for me to make up the Kalk each night and I already have an auto top off so I don't need to make up for evap. I have been using the Seachem Calcium and Alk products just because it's easy to pop 4 cap fulls of that stuff in at my convenience. The problem with that is 1, that stuff is expensive and 2, I have a hard time keeping my levels as high as what I was getting when I was dosing Kalk. Not to mention the fact that I have to test my levels all the time.

My Calcium right now is 400 and my Alk is only 2.5. Sounds like the Nielsen might cure that problem and rid me of the expensive Seachem products.

One question though. Most people dose Kalk at night to keep the PH from spiking too high. If I tie my auto top off with the reactor what's to keep me from going nuts on the PH during the day when the auto top off is making up the bulk of the evap from the heat of the lights and fans? Right now my PH is normally around 8.1 - 8.2 at best. So maybe I will be ok? I guess my daily avap is around 3 to 3.5 gal. My total system, sump and all is around 95g.

[Ninong]

Originally Posted by Tie

With my current 72 Gal my problem has been dosing Kalk. Because of my schedule it's hard for me to make up the Kalk each night and I already have
My Calcium right now is 400 and my Alk is only 2.5. Sounds like the Nielsen might cure that problem and rid me of the expensive Seachem products.

There is nothing wrong with 400 ppm Ca and 2.5 mEq/L (7.0 dKH) alk. Both of those numbers are absolutely normal compared to NSW. You might want to try to get your alk up to 3.0-3.5 mEq/L but it's certainly not a problem where it is right now.

One question though. Most people dose Kalk at night to keep the PH from spiking too high.

I slow drip my limewater at night over a period of 6 to 8 hours so that it will help somewhat to counter the normal drop in pH at night when photosynthesis is in its respiration phase. Some people actually slow drip limewater 24/7.

If I tie my auto top off with the reactor what's to keep me from going nuts on the PH during the day when the auto top off is making up the bulk of the evap from the heat of the lights and fans? Right now my PH is normally around 8.1 - 8.2 at best. So maybe I will be ok? I guess my daily avap is around 3 to 3.5 gal. My total system, sump and all is around 95g.

I know some people who use a litermeter dosing pump to dose limewater 24/7 as replacement for evaporation and that seems to work fine. What you want to avoid when using limewater as your auto top-off water is having a "bunch" of it dumped at one time. Some auto top-off systems aren't very well set up to handle limewater because they make their water additions in large batches. This is not a good idea with limewater. Dumping too much of it all at once can cause harm by spiking the pH.

[Tie]

You rock Ninong!

I've read that the alk level is about 2 to 2.5 in the big blue but I also see every reefer out there tries to keep both their calcium and alk higher than the norm. I suppose this helps to stimulate better growth and health in the captive reef? Or perhaps it counter acts some deficiency or other problem that arises in our home system that is yet unknown to me. What ever the case it's an interesting topic.

I may try that 24 hour drip. I'm thinking I could remove the electronic float that's in my sump and hook the fresh water supply directly to the reactor. I'll then determine my evap rate and set the drip on the reactor accordingly (I assume that's how the reactor works). Might be a pain to get the drip rate dialed in but sounds like it will be well worth it in the long run.

I thought about a DIY reactor but then I've heard a few horror stories. I've got too much time, money and love in this project. The potential for disaster with a Nielsen is high enough that I'll probably find a nice reliable, time tested and proven manufacturer. I see Andy (MRC) makes them. I really like my MRC skimmer. I also found this http://www.ecotechmarine.com/products.html Never heard of them but I found a thread somewhere else where a couple people had good things to say.

Anyway, thanks for the lesson and advice.

[Jimbob]

The MRC nilsen reactors get really good feedback from what I have read, as do the Precision Marine nilsen reactors.

I have also heard great things about the Deltec Kalk Stirrers, however they are not easy to find in the U.S. and they cost just as much as a calcium reactor.

The Aqua-medic nilsen reactors operate on a slightly different principle, using an internal pump that runs 24/7... for some reason, this just makes me a little nervopus about impellers binding and burning up, fire hazard, etc. so personally, I would not use one of the Aqua-Medic units.

Given my choice right now, I'd prolly go with the Precision Marine first and the MRC unit second... mostly because the PM unit uses a powerhead type pump to stir the kalk and is therefore very easy to service and replace if anything wears out.

Of course neither unit is in the budget right now