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Bubble, bubble, toil and trouble - more on substrates

Hi Everyone,

In APD V3 #174, Kevin Reavis is asking for recommendations on which
additives to add to the substrate of his new tank. Apparently, he has read
everything on the Krib and is planning a hybrid approach - taking what he
hopes are the best parts of several different methods to arrive at a
satisfactory solution to the set-up of his tank.

Talk about deja vue - I've been there, done that, and suffered the
consequences. But before I relate parts of that story, I'd like to address a
couple of things that Kevin mentioned in his posting:

> My
> plan is as follows:  (comments, opinions & suggestions appreciated:)
> ...
> 2 full spectrum 6500k for the plants & 1 blue actinic to bring
> out the colour in my fish

There is no need to use actinic lights over a freshwater plant tank. The
plants you are going to be growing and the fish you will have in the tank
are found naturally in shallow waters which don't suffer appreciably from
wavelength absorption (like coral reefs experience). Stick with full
spectrum, high CRI tubes and your plants will grow beautifully and your fish
will look fine.

> spray bar positioned vertical to minimise surface movement

I use an Eheim 2260 (a BIG canister filter) on my 120G plant tank and got
rid of the spray bar pronto. Eheim (and others) make tubing elbows which
will allow you to route your return water flow into the tank in a manner
which is more natural than the high pressure pinpoint streams caused by
spraybars. And the return can be positioned in such a way to minimise
surface disturbance, if that is what you desire.

> Substrate: (thanks Steve)
> Bottom layer - 2 bags flourite + 2 large boxes dupla laterite
> Middle layer - topsoil+peat+vermiculite+perlite+well aged compost
> Top layer - 3 inches of medium grade sand blast sand (silica)

Oh my God! This is where I'd start to get REALLY nervous. You are
formulating a Witch's Brew and might end up with a frog in your tank in
place of a prince.

In January of 1997, I set up my current 120G plant tank with a similar (but
slightly different) concoction of substrate components. Based upon my
experience with my tank and depending on your level of experience in keeping
planted tanks (I have about 30 years under my belt) this can either be a
good thing or an invitation to disaster.

In the bottom of my own tank, I placed a custom made copper manifold (epoxy
coated) through which I circulate warm water (the water is heated in an
insulated external tank and pumped through the manifold via a powerful Eheim
pump). This was designed (I had hoped) to provide substrate heating at less
cost than the Dupla Substrate Heating Cables and without the risk of
electrocuting myself with a DIY transformer. The circulating water is
approximately 90F (heated by a 200W submersible aquarium heater) and I have
been able to measure a temperature gradient of 4F between the areas directly
over one of the manifold tubes and adjacent areas between the tubes. In no
case does the gravel ever reach 90F (the highest temperature of the gravel
is 84F directly over a tube, with a value of 80F being recorded when the
thermometer is inserted into the space between the tubes - which are on 2"
centres). Tank water is maintained at 77-78F using submersible heaters.

As for my own substrate mix, I, like Kevin, consulted the Krib, Steve Pushak
and every other source I could find to come up with the "ultimate substrate"
for my new tank. I used two "layers" of substrate, the bottom layer
containing a mixture of the following:

1. Duplarit G (at the rate recommended by Dupla, 1500g for my size tank),
2. 10 lbs of Red Art Clay,
3. approx. 1 litre of Vermiculite (powdered in my kitchen blender - yech!),
4. a large box of Sera Peat Granules (chosen because they would be less
likely to         disintegrate and foul the water column),
5. 2000g of Aqualine Buschke "Terralit".
6. Sufficient crushed granite gravel mixed with the above additives to just
cover the copper heating manifold (approx. depth of this layer is 1.5")

The top layer of gravel is approximately 4" deep and composed of pure
crushed granite with a particle size of 1-3 mm.

Following everybody's recommendation, I planted heavily right from the start
and the tank is lit using 3 175W 5500K Metal Halide bulbs. CO2 was supplied
by DIY Sugar&Yeast and dispersed into the intake of a Power Head. This
produced a fine mist of teeny tiny bubbles of CO2 throughout the tank but
did give me a CO2 level of between 15 and 20 PPM (La Motte CO2 test kit). I
have since constructed a CO2 reactor which uses Dupla Minicascades and seems
to be much more efficient (cost me all of $20.00 to make vs. $150+ for the
Dupla Reactor S which it approximates).

Now, the problems which I have experienced with this set-up - and there have
been a few:

A LOT of plants did not like the substrate, at least not initially. Amazon
Swords suffered root rot for the first couple of months, as did Crinium
bulbs. Some stem plants grew like gangbusters, others would not put down
roots. Giant Hygro simply refused to grow, but Dwarf Hygro was OK After
about four months, I started placing Crypts into the tank and they seemed to
have no problems, but neither did they explode into furious growth.

At around the six month mark, my health forced me to pretty much leave the
tank alone for a protracted period of time and as a result evaporated water
was replaced with Toronto tap water (maybe it should be bottled and sold as
Algae Fertiliser) instead of the R/O water which I had been using. Massive
(majorly massive) green algae blooms followed, necessitating the removal of
much of the fine leafed plants from the tank. I also had Red Algae and Beard
Algae on my Crypts which I solved (or at least kept in check) by physically
removing the affected leaves. Eventually, it went away.

For several long months, the tank was just "there", being mainly ignored
except for the addition of a bit of food now and then and the daily addition
of a few gallons of water to make up for evaporation. CO2 fertilisation
became spotty and then stopped altogether as I just wasn't able to do it due
to my illness.

Recently however, I have been able to get back on my feet and have taken
matters more in hand. I was afraid that I might have to totally break the
tank down completely and wash all of the additives out of the gravel and
start fresh but once I started pulling out plants, I discovered an amazing
thing - really, really healthy root systems on my Vals and Dwarf Sags, and
carpets of Crypts with the most wonderful white roots. It seems that the
substrate had finally settled down and was working well. I also tested the
water and discovered that my Phosphate level was 0.25 PPM and Nitrate was 1
PPM (La Motte test kits). Obviously, the luxurious growth of my Java Moss
and Java Ferns had done a lot to pull a lot of the gunk out of the tap water
I had been adding over the preceding months.

I vacuumed a lot (but not all) of the accumulated mulm out of the gravel and
changed 50% of the tank's water (this time with R/O) and then replanted,
mainly with Echinodorus cordifolius, several new species of Crypts and some
Anubias. Stem plants were limited to some Dwarf Hygro, Bacoba and Ludwigia.
Everything is growing well, much better than I expected after such a major

It seems that the most important ingredients for my tank's eventual success
were time and patience, time for the substrate to integrate itself into a
working system and patience for me to finally relax and let Nature take its
course. I would suspect, but have no proof, that the fact that my substrate
employs substrate heating has contributed to the fact that it now, over a
year after having been installed, allows me to grow pretty much anything in
the tank that I care to. There is absolutely NO indication that the
substrate is "tired" or in any need of changing. I suspect that given proper
maintenance (i.e. vacuuming) it should last several more years before I will
have to re-do it.

Please note that the only organic material I added to my substrate initially
was Sera Peat Granules. I didn't use compost or topsoil as Kevin is
proposing to do. At this point in time, over a year later, my substrate DOES
contain a lot of organic material, sourced from the mulm which naturally
builds up in a tank over time. When I vacuumed the gravel, I removed some,
but certainly not all of this material. Organic mulm will mineralise over
time and release nutrients to the plant roots.

> I started my 90 gal plant tank 2 years ago as a complete newbie and was
> convinced that I needed every chemical concoction & gadget known to man to
> make it work right - (my LFS loves me!:) so I have been thru lots
> of stuff, trial and error and money and still did not have the kind of
> plant display I wanted.
> ...
> I used to just want to grow plants - now I want to become a "gardener" -
(thanks Karen:)

If there is one thing I have learned in this hobby, it is the value of
patience. No amount of gadgetry or chemical additives will ever make up for
a lack of it. Less definitely can be more and we all need to relax. This is
after all a "hobby" for most of us.

> 1.  Which layer do I put the additive into?

I would recommend (as does Dupla) that you place your additives in the
lowest level of the substrate. As I have discovered when I recently re-did
my own tank the plants will develop very extensive and deep root systems -
they will find the nutrients that they need in the bottom layers of your

> 2.  Is there any benefit to mixing "aged" gravel into the bottom & middle
> layers to give the bacteria a boost?  If so, into both layers or just the
> middle organic?

I've always used a couple of handfuls of "aged" gravel in newly set-up
tanks. You get the beneficial bacteria needed for the start of the Nitrogen
Cycle and you don't have to buy commercial Bacteria cultures of dubious

> 3.  I want to use the plants, driftwood & fish from my 90 gal - but it is
> currently covered in hair algae.

If the "hair algae" is bright green, and not in fact beard (red) algae, I
would recommend that you just scrub the driftwood under a strong stream of
water and remove the most affected leaves from your plants before
re-planting. My plants cost me too much to subject them to bleach.

Aquarists spend far too much time worrying about algae. If the tank
conditions are good for higher plants, they are probably going to be good
for algae. One of the most important factors to reduce the prevalence of
algae is to keep the water column relatively nutrient poor and free of
phosphates. Having lots of rapidly growing higher plants also will suck up a
lot of extra nutrients which could be used by algae to gain a foothold in
your tank. But those who expect to have totally algae free tanks are (in MY
opinion) a little too retentive in the lower regions (if you catch my

> 4.  Also - I want to transfer my mature canister to the new tank.

If the canister has been cleaned within the past two months and is not
overly loaded with detritus, this is something that I would recommend - you
have a working biological filter inside of that canister filter and that
will greatly enhance your tank's chance of success.

Sorry if this has gone on a bit long.

James Purchase
jpurch at interlog_com