>From: didi at wwnet_com (Didi Soichin)
>Date: Thu, 28 Mar 96 22:03 EST
>Subject: Tank disaster
> I hope somebody can help me figure out what's going on with my tank and
>what is to be done.
> Tank specs: -tank: 29 G, 80 l water volume, 15 l gravel volume (I use
>liters for dosing the Dupla Fertilizers)
> -substrate: 50 lbs "filter" gravel 1-3 mm size, bottom
>1/3 mixed with 250 g Dupla laterite; Dupla heating cables 24V/25W with
> -lighting: 2X20 W Ultra-Trilux in double-bulb strip light with
>reflectorizing material, for a total of 2760 design lumens; 11 hrs/day
> -filtration: Eheim 2213 Plus filled with mechanical and
>biological filtration material, output is spray bar 2" below water
> -plants: an assortment of fast growing species: several
>varieties of Hygrophila and Echinodorus; Ludwigia, Bacopa,
>Myriophyllum, Rotala and Lilaeopsis
> -algae crew: 2 2" SAE, 1 Ottocinclus, 1 2" Peckoltia, not fed
> -temp: 76 F
> -tap water: KH 4, GH 6, pH 7.6
> Here's the anatomy of the disaster: (I made several measurements
>during each day, I will post only the ones taken at similar times of
>day, all other parameters -temp, lighting- were kept constant)
>Day -2: I treated the gravel with a 1:1 dilution of 31% muriatic acid
>to eliminate any "lime chips" of which _very few_ showed up at the HCl
>test. I know I shouldn't had, but I had a gallon of muriatic acid
>sitting around and nothing to do with it :-). I washed the gravel
>_thoroughly_ in small batches. It didn't smell like Cl at all after I
>rinsed it if that makes any difference. It dried halfway in the next 2
>All the following events are approx 24 hrs apart, in the evening,
>1-2 hrs before the lights went off
>Day 1: I setup the tank, filled it with water, added 4 Duplaplant
>tablets and 40 ml of Duplagan. In the evening I planted the tank and
>later on I added the fish. I started injecting CO2 in the intake of the
>Eheim from DIY yeast, 60 bubbles/min.
>Day 2: Plants bubbling like crazy. Fish moderately passive but I
>thought it was due to the new environment. Then
>I noticed one big Malaysian snail totally imobile (never seen
>something like that ever since I got them). So, I tested the water,
>something I should had done _way_ before this incident.
> pH below 5.0, KH=0
> 75% water change --> pH=6.6 KH=2.5, the snail (that saved my
>fish) assumes his usual activities as I pour tap water into the tank.
>Here's another use for trumpet snails, pH indicator :-)
>I thought it was CO2 overdosing so at this point I stopped injecting
>Day 3: Plants bubbling, fish and snails OK from now on. One drop of
>Duplaplant 24/day added from now on.
> pH=6.4 KH=1.5
> 90% water change (doesn't have chloramine)--> pH=7.0 KH=3.0
>Day 4: pH=7.0 KH=2.5
>Day 5: pH=7.0 KH=2.0
> frustrated, I added 1 tsp of baking soda -->pH=7.6 KH=3.5
>Day 6: pH=7.3 KH=3.0 GH=3.5 (tap water again is pH 7.6, KH=4, GH=6)
>In the remote possibility of dealing with biogenic decalcification
>(but AFAIK it doesn't go that fast ,pH should rise not drop and it
>shouldn't affect GH) I started injecting CO2 at a rate of 30 bubbles/min.
>Tomorrow, if the KH keeps dropping I will stop the CO2 and remove the
>only piece of driftwood in the tank just in case.
>Amazingly enough, the fish are very active, munching on invisible algae
>and don't seem to be affected by this abuse. The plants are doing fine
>but it might take a while until they show any signs of damage. For now
>they're bubbling and growing. Lilaeopsis is spreading runners, the
>Echinodorus-es already put out a couple new leaves and the stem plants
>grew about 2" in this past week (I transplanted them with good size roots
>from my 10 G "jungle").
>So, my pH, KH and GH are dropping. I *guess* the most logical
>explanation would be that the gravel wasn't rinsed enough and is
>leaching HCl. The daily drop in KH is smaller that in the first couple
>of days so probably the tank is going towards equilibrium, but who
>knows how long that is going to take ?
>So, why is it happening and what should I do now ? Replace the gravel,
>though this would be a torture; wait until the tank stabilizizes;
>compensate the daily drop in KH with sodium bicarbonate to speed up
>the buffering ? And ,if I wait, does anybody know how long it might
>take until the tank is stable ?
>I will appreciate any suggestions or comments.
>I apologize for this monster post, I just wanted to be thorough. I will
>shut up now.
> Didi Soichin
> didi at wwnet_com
> Westland, MI, USA
This doesn't sound like a REAL disaster, where everything dies and the
neighbors complain about the smell. After all, a temporarily immobilized
trumpet snail isn't so bad. :-)
I agree with Karen Randall that it sounds like a little acid is still
coming out of the gravel. This won't go on forever, and partial water
changes and not overdoing it with the CO2 should keep everything happy.
Hydrogen ions are pretty mobile, and the tank should reach equilibrium with
the gravel in a week or two.
You can increase the amount of calcium in the water if you want to. There
are several ways of doing it. A slow, safe way is to get a seashell or two
(not too easy in Michigan!) and put it or them in the tank and monitor KH
for a few weeks and take it out when the values are to your liking. You
can also do this with egg shells, but you should soak them in water for
several days first to remove soluble proteins. The problem with the egg
shells is that they don't look very nice. I have used clam shells or egg
shells to raise the amount of calcium in tanks where I used the rather soft
water from the Pearl River, which runs through Jackson, Mississippi. It
took several months for the values to reach equilibrium.
A faster, but less safe way is to add lime. Lime is CaOH2, calcium
hydroxide, and it dissolves in the water and reacts with CO2 to make CaCO3,
calcium carbonate, which makes a cloudy precipitate. Depending on how much
CO2 is available, more or less of this precipitate will react with more CO2
to from Ca(HCO3)2, calcium bicarbonate, which will dissolve again. You
want to do this vary carefully with small amounts of lime. Too much will
suddenly raise your pH. I would try just a pinch in a 15 gallon tank, wait
a day and measure my values.
A way that is between the above two in safety is to use,instead of lime,
ground limestone, which should be available at garden stores. This is a
mixture of calcium carbonate and magnesium carbonate, usually, and It will
raise values more slowly than lime, but, unlike the seashell, it can't be
taken out if you think you added too much. Again, if you want to
experiment, add a very small dose and wait about a month before considering
Paul Krombholz Tougaloo College, Tougaloo, MS 39174
Where students and faculty are suffering from spring fever!