Hi,

Lately I see that growth on the left side of my tank is not like it used to be. Yesterday, after 3 weeks that my Eusteralis looked bad - I pulled some of it out and saw that the roots are black with bad smell. Pulling this one tiny plant dirtied the water with many brown pieces.

The substrate is as follows: 1 inch organic substrate (JBL), thin layer (2Kg per 200 galon tank) of crushed laterite balls and topped by 4 inches of small quartz 1-2 mm.

Now I suspect that since the quartz is very small and since it's depth is high (4 inches) then I have too many anaerobic holes.

Should I re-start the aquarium? take all fish and plants out, etc? Can I do a partial job of taking out half of the amount of quartz? stir it somehow? Can I do only the left side of my 8 feet tank and then after two weeks the right side?

Aviel.

 

I have never used this combo for substrate but 4" is to much IMO, I never go over 3". Have you been vacuuming the substrate when you do a water change? I do not think I would tear down the whole tank but I would take some substrate out and then give the remaining substrate a good vacuuming.

 

Aviel,

I wouldn't jump to any conclusions about your substrate. If you have the same substrate everywhere in the tank and you only have problems in part of the tank then maybe the problem lies somewhere else. You might uproot a few more plants and check the condition of their roots. In particular, check roots on plants in other parts of the aquarium and compare to plants growing in the area you're concerned about.

Natural aquatic soils are pretty much always anoxic just millimeters below the surface. As a result, aquatic plants are well-adapted to deal with substrate anoxia. I have found that plants will reach with their roots into anaerobic areas and develop thick robust roots. The roots are coated with a black film and smell bad, but if you wipe the film off you find that the root underneath is firm, white and health.

Anaerobic conditions increase the availability of both ammonia and iron to plants and may help with a few other nutrients as well.

If after a closer look you still think that anaerobic conditions in the substrate are causing problems for your plants then I think your best approach to the problem is too take the tank down and replace the substrate completely. Half measures are likely to work half way.


Roger Miller