Questions for Marko Haaga


New member
Hi Marko,
I guess from the reef tank of the month article that you are from Germany. I am from Italy and have been in the reef addicts club for some time.
I have a couple of questions about your tank which, by the way, is such a wonderful tank (many compliments).

First I would like to know a little more about the use of a pepsi bottle to double the reactor's chambers. Do you just poor the water coming out from the main reactor flow inside the pepsi water and then come out? Where exactly go through the two flows: the in-flow and the out-flow? Do you add movemnt to the bottle?Plus I don't know exactly how the recirculation system for the CO2 might work. Is it a DIY method?

Second question is about the distance you keep your HQI from the water level. In the picture I see I would say 25/30 cm.

Finally I would like to abuse of your patience by asking for some suggestions. I intend to buy the Zeovit filtration media that I have seen on a German site. Some of my friends here in Italy are using it with satisfaction. What do you think about it?

Well these are a little more than a couple of questions, but I'd like to get some advise from you.

Thanks a lot - hope you'll reply.


Hi Matteo

Many thanks for your comments.

I don't live in the Germany, but in Finland, but I have to admit that the "German school" of reefkeeping has affected my reefs a lot in the past and also will do in the future.

That Pepsi bottle is only a second chamber and arranged so that the water comes in in the bottom of the bottle and leaves out from the top of the bottle. The is no internal recirculation in the Pepsi bottle only slow flow. The second chamber raises the pH of the effluent of my reactor about 0.2 pH, which helps to keep the pH in the tank good.

Yes, the HQI light is about 25 cm above the water.

I have also used Zeovit for about 4 months now and I am very pleased with it. During summer we had a renovation in our house, and I had to break down my tank, but it to the garage for 2-3 months. I bought a bigger tank (840l) which has been running now for three weeks. During that garage period I used the Zeovit method and everything was in excellent condition. Although the tank was light by T5 lights the colors of the corals were even better than before if possible. My new tank also has Zeovit filtration and the corals look excellent although it is only 4 weeks after adding water to tank. There was very little brown algae for about a week, but thereafter no algeaproblem at all. And that was the same with the tank in the garage. And that has happend never before in my over 10 years of reefkeeping and multiple starts after break down of an overgrown reef in my tanks.
For me The Zeovit method is THE METHOD I will surely use also in the future maybe untill something better comes out.
Thanks a lot for your reply. I would still like to ask some more detailed questions, hope it's ok.

Regarding the Pepsi bottle, I think I will "copy" this method. I truly like it and think it is very smart. I was just wondering if you use a different media in the bottle or if it is just some kind of calcium media. Do you also use Argamax as the Us reefers do?

About lighting I have seen on your tank of the month article that you have changed from Ushios to Aqua Connect. What do you think about BLV AB Aqualine and Radium? Here in Italy there are many discussions about lightining the aquarium. I use two 250W BLV and I am not very pleased with them.

About the Zeovit I am happy that you use it. I will start this week and try to keep a record of the changes I will see. Some of my reef frineds are a little worried about the method because you can't explain exactly how it works. I have read here on reefcentral a topic between chemists and rock experts in which they gave an eplanation that mainly consists in the effectivness of the zeobak (or zeofood) in apporting iron that ties to the PO4 molecules and makes it easier for the skimmer the removal of such PO4. What do you think are the insite to this new method in terms of chemical reactions/exports?

I thank you again for any reply you will be able to give me.


I use mixture of different kinds of media in my calcium reactor. In the main reactor there was and is Aquamedic Hydrocarbonat (or Rowalith) and 10 % of Grotech Magnesium Pro to keep the magnesium in good levels. In the second chamber (Pepsi bottle :) ) there is crushed coral, 10-15 mm in size.

If the bulbs you mentioned I think the BLV is the best, but you should not use them without suplemental actinic lights. I want to have also yellow wavelenghts in my HQI to show the red color in the corals better, but BLV itself seem too yellow to my eye, so I add some actinic light to it, JBL Solar Ultra Marine Blue has the best spectral chart I have ever seen. Radium might be good if you compain it to say 2 BLV. AB Aqualine is quite good, but I think it might have a bit too much of UV radiation.

I surely don't know what the mechanism behind the zeovit system is, but it seem to work nicely. There is data that both nitrate and PO4 goes down, so it greats nutritient poor (dissolved) enviroment as in real reefs. They say that the skimming is important thing in their system, and it really seems so. I have done a little changes to my skimmer so direct comparison is impossible, but it seems and in my garage tank is seemed that skimmer pulls out much more of very dark skimmate than before I used zeovit. I don't have a clue what it pulls out, but my tank is better than ever, and there is really a data to show that PO4 and nitrate do go down. And the system has something to do with iodine and iron, because they warn especially not to add them to the tank so much than before.
Thanks again

Thanks again

I guess you have given me all the information I needed. I invited some of my fellow friends to visit this post. Matbe some of them will ask you more things. For now thanks and maybe I will let you know if my tank goes better with the zeovit system.


I Haaga,
I am Mat's friend and I have some question:
Do you have some artificial lighting to your Zinn plancton reactor?
Do you think that it works also with day-light normally from a window?
You don't have notice difference now with the T5 lighting and you still have this in your new tank?
When you started with the Zeovit system you stop also feeding corals?
I also compliment for the Pepsi-bottle and do you think that can also work fine if I put in the second chamber "Pepsi-bottle" only the Magnesium Grotech?
Thank's in advance for you replay.
By Aster

Yes, the reactor has Sylvania Aquastar 15 w fluorescent tube as light. If you live in sunny part of Italy and your window faces to the south, yes I believe that you get more than enough light if you keep the reactor behind the window.

Now I have 3 x250 w metal halide lights, and the tank is about 4 weeks old. I haven't yet noticed any major differences, some chenges maybe, but it may be too soon to say.

I have feed my corals as I used to with zeovit system also. My feeding has always been quite minima. I use mainly Salifert Coral food, Marine de Luxe and some AB Plankto, know I have not used live plankton, because my reactor is down, I am planning to start it again in next weeks or so.

They say that you should use only 10 % of magnesium media and 90 % of calsium media, if you use more, too much magnesium dissolves to water.