New ideas for reef aquarium filtration

20 days without activated carbon and Purigen!

Recently I have been experimenting with some new ways to filter reef aquarium water. Here are some notes about the current situation. I will provide more thorough documentation at later time.

CaCO3 Enhanced mechanical filtration

Due to heavy feeding, DSB and good amount of live rock the detritus/plankton production in my tank is high. I also have fishes that keep digging the substrate and that introduces a lot of small particles to the water column. I have noticed that the amount of particulate matter in tank water is much higher than in natural waters when viewed from the side. I have also noticed how many of the fine filterers (sponges and worms) have hard time dealing with all this stuff floating around.

For these reasons I have been using mechanical filtration (powerhead and filtration mat) many years. I have found it to be excellent nutrient/waste export method. I actually think it is potentially the most efficient method available for many reef tanks. For DOM I have used large amounts of activated carbon together with Seachem’s Purigen.

But even with all this filtration the water remained cloudy, most likely due to my increased feeding.

So I decided to start to experiment with home made calcium carbonate slurry in order to enhance the mechanical filtration. The idea is to make very fine CaCO3 powder in about 50:50 mix with pure water and add this slurry to mechanical filter. This would then fill the small pores of the filter and thus improve the efficiency.

I also knew that fresh CaCO3 will bind phosphates and organics and thought that doing this might very well reduce the need for fresh GAC.

So far the results have been much better than I originally anticipated: I have completely stopped the use of GAC and Purigen and yet the water clarity and transparency are much better than I have ever had, even with much less feeding. At this time I think I will never again need to buy GAC or Purigen.

I dose 20 ml close to mechanical filter in sump every morning, turning the feed pump off for a couple of minutes (as long as it takes to drink a cup of coffee ) so that only few particles will reach the main tank.

Making slurry is very easy although there are many ways to do it. I think there is still some experimentation to do but currently I’m using about 2:2:1 CaCl2:NaHCO3:Ca(OH)2.

PVP Enhanced skimming

Due to frequent and heavy feeding of planktonic invertebrate foods, my skimmer is only running half of the time during daylight period. The foods contain oils and other substances that reduce the skimmer performance so actually skimmer is probably working only 25% of time. Most likely this would not be of any concern if I didn’t also have many fishes, some of which are heavy feeder (I feed fishes 4 times a day also). Thus I need efficient export methods for DOM.

All this has lead me to think about ways to increase skimmer performance. I have been using PVP as a skimmer aid for many many years but only in exceptional circumstances and only as a single shot dose.

Currently I’m dosing a dilute solution of PVP with the help of dosing pump. The daily dose is 24 x 4 ml of a solution made with 700 ml water and 30 ml hw hydrokoll (a source of PVP).

Results so far have been excellent although the dosing is certainly subject to change.

Tags: chemistry, equipment, food for thought, Husbandry, nutrients, tank

This entry was posted on Monday, April 27th, 2009 at 15:42 and is filed under Husbandry, Ideas and misc. You can follow any responses to this entry through the RSS 2.0 feed.