NANFA-- That whole sandbed thing.

Todd Crail (
Fri, 31 Jan 2003 22:59:17 -0500

Greetings all...

Well now that I'm 3 months into a sugar grained deep sandbed as substrate
and have watched everything work as expected so far... I thought I'd get a
picture and talk about it a bit. With certainty, the real meat of this
discussion is about 1 year and 9 months down the road once any type of
"honeymoon" is over with it, but maybe there are some who'd like to
experiment with this now.

That thar is a sandbed :) It's about 5" in the deeper sections (this is a
normal 75 gallon). I bought the playsand at Home Depot for $2 a bag. 75
gals of substrate for $6, when did you last pay that? :)

Within the bed, I've mixed a bag of Seachem's flourite for extra root
nutrition (the flourite will get your cost savings back tho ;). The surface
layer is all flourite and pea gravel. The bed slopes toward the back so
that it's about even with the far left corner there (the 5" depth). I did
this to create a grade from front to back so I could aquascape in some
ornamental rocks and such. The intention is to only have about 1/2" to 3/4"
of rocky material up top.

Why is it like this still? I wanted to compare growth on different plants
in different segments. Some in shallow gravel, some in deep gravel. Let's
just say those that hit the sand faster establish better and grow waaay
faster. Some stuff on the deep gravel is still going as previously
experienced... Super slow to withering. For example, I've always had
trouble with val. Didn't matter the kind. Dunno why. I put it in sand and
there it goes. Same story with sagittaria. And all plants are forming
super long roots (even bulbs like apongeton and nymphea? I have an apongeton
that's been in bloom on one stalk or another for a month now lol). They're
starting to make their way out to the edges so I can see how deep they're
penetrating. It would be interesting to cut a hole in the foam insulation I
put underneath (my $3 solution to a $200 undergravel cable heater for 'warm
feet' heh) and see where it's all at :)

I do add fertilizers. I've been adding Sera's Florena for soluble iron and
micronutrients, potash for potassium and sulfur, and epsom salts for
magnesium. I was doing this all before in a flourite only bed (which a
flourite only bed is recommended at the lfs of course ;) and was not
experiencing even a fraction of the success.

There was one other change.. And that was putting glass tops in and sealing
up the gas exchange. I was not doing this prior (had it open top) and the
additional CO2 is definately a factor... But remember... I'm getting the
same sort of growth I had prior on the deeper gravel... So I kinda throw
that out. At the same time, it's arguable that the respiration in the sand
is an additional CO2 source (no external CO2 source, even tho all the
equipment is sitting right next to the tank lol). So it goes many ways. It
would be nice to be able to quantify things a little bit better.

There have been other benefits as well. The water was transfered from
another 75 when I did the tank move. Initial nitrate reading was ~50ppm.
Pretty crappy huh? Once some plants had reestablished themselves, man the
whole thing took off like wildfire. I haven't seen a nitrate in 2 months
(weekly tests). I only did one 15 gal water change back in early November
just because, well, "you're supposed to" but I haven't fussed with it since.
Just tested for nitrate to see how we're moving along. I've also only
scrubbed the glass twice since this system's inception. Wow. Now I have
all this time to take pictures :)

Again, the jury is still out on wether the sand is denitrifying or the
plants are able to absorb all ammonium and nitrate with their roots all good
and happy. In either case tho, together they're limiting algal growth and
keeping the fish all happy. Oh, and the Farmer too :)

So shortly when I go to set up the next native tank (gonna be another 75
now... we'll see if it's back to the 125 next week ;) I'll pull off a
majority of the top layer of the gravel as seed for the next tank. Then
I'll aquascape as intended :)

Same experience in the 30 gal native tank too, except that this sandbed is
only 3" max due to the limited verticle tank space. And when I moved that
sandbed a few weeks ago, I never even caught a whiff of sulfide. May be too
early to call that good tho ;)

I've yet to work with benthos (bottom dwelling critters) to see who will be
beneficial and who will not. I'm going to work with that this summer
outside in the yard so I don't violate my "3 tanks in house" ruling. Should
be interesting.

So for now... To heck with all these rumors of black roots and room choking
sulfide nasties... The plants live in anaerobic substrates in the wild...
Dunno why it'd be any different in a tank. Apparently all these authors and
'experts' have never walked thru the muck huh? ;)

And for a piece of shameless promotion for rainbowfish... check out the rest
of the pics at:

They're native if you're from Oz or PNG right? :)

Night all... :)

I hope you know that this will go down on your permenant record.
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