Planted tetra tanks: my dialog with NetMax

[Trapper]

Netmax wrote in e-mail, and I re-post with edits:


[Modular filters in planted tetra tanks]



[i]
> Other than the heating & driftwood, I would not recommend [the heroics
> in filtration, since there'll be a low fishload].
[i]
> Any concentrated filtration system (ie: your FB) is a source of
> maintenance and risk exposure (if it clogs, during a power failure
> etc) which has no justifiable benefit while it is working.
> Ditto for micron filters [***]

It must be said that *any* biological filter will suffer if it clogs
or if there's a power failure. I can see what NetMax is probably
saying between the lines, though: a FB filter goes anaerobic and
becomes a tomb for beneficial bacteria much faster/worse than other
types of bio filter.

Secondarily, if there's a pump failure then the daisy-chained modular
stuff ALL goes. Not so if you're using other kinds of systems with
multiple pumps and the like.

> [UV sterilizers cannot differenciate between bad & good bacteria]

Implicit in mentioning this is the concept that there exists an
important
population of beneficial bugs suspended in the water column.
Brand-new
tanks aside, I think the beneficial bugs - at least as concerns
biological
filtration - live not suspended in the water but attached to various
surfaces (bioballs). If this assumption is incorrect, and there are
good bugs whose maintenance in the water column is necessary, I'd love
to know more about
that (I'm a microbiologist by training).

If I'm using a dedicated and oversized biological filter, then I
assume
all my good buggies will live there in abundance. If some should
detatch and come to harm in the maw of the UV sterilizer, it's
probably
no big loss. I'll happily take that loss in order to kill everything
waterborne that isn't a fish or plant.

(We'll take as read the various caveats on UV sterilizers de-chelating
iron,
and so forth. Those are amply covered elsewhere.)

> The objective (imo) for filtration is to achieve the highest efficiency
> needed to meet the application, with the lowest amount of complexity to
> maximize the reliability. Tetra tanks demand a very low efficiency which
> you should take advantage of.

I think a good take-home message is in this. I think NetMax hints at
the
precept of avoiding as many single points of failure as possible,
while
still maintaining a workable system.

To my mind, there are points of failure which can lead to big
NON-IMMEDIATELY fatal problems. You have one water pump running the
whole
system; it gives, and NOTHING works until you get the replacement in.
Your
electricity goes out, and you don't have a backup generator. You have
one
heater adequate for your tank, and it sticks on. These kinds of
things.
We engineer around these by trading simplicity for a bit more
failsafety.

As far as biological filters go, I think I'm concerned enough
about it that I'll think about running two different and separately-
powered ones.

> [...] If you use CO2, try to have some redundancy (two
> independant staged CO2 dispensers) and the closer you maintain your
> pH to your natural conditions, the greater your operating reliability.

I concur in this, to the extent that I'll be relying on CO2 to
influence
the pH of the system. If pH stability is so crucial, I wouldn't want
to leave it in the hands of just one CO2 tank/valve. Presumably if I
note failure in one system, the other can be throttled upward to
compensate.


> [For tetras, pH stability is important and osmotic pressure consistency
> is VERY important]

Part of why I'm looking to keep these teensy fish in such a big
system.
I've got ideas/questions about this, look for them in another thread.

> [***] [In heavily planted tetra tanks, the] tank will be mostly
> filtered by the plants, I go with low flow canisters which provide
> a high level of efficiency (media to flow ratio), using various
> sponge densities and sintered glass (and peat pellets if you
> insist ;~). No carbon.

The idea of a low-flow canister has its appeal. A degree of
modularity,
and simplicity inheres. Various flows are out there.

However - and this I maintain purely as a matter of personal taste - I
feel I can get this all to work using w/d, while leaving myself an
easy way to expand capacity. I'll start it out with a low flow rate
and little media, and if the plants keep up, fine. If I start really
increasing my fish load and the water parameters dictate then I'll add
more bioballs, and another pump in the sump.

--Trapper

[Dr Engelbert Buxbaum]

Trapper wrote:

> [Modular filters in planted tetra tanks]
> [I worried about w/d filters' outgassing power making CO2-injected
> tanks difficult to maintain, and suggested use of modular system
> with a fluidized bed biofilter, micron filter, UV sterilizer, heater
> on my planned 125-gal tank instead of a w/d hodgepodge.]
>
> [I also mentioned CO2, peat/driftwood to get pH to 6 and softness to
> discus-like levels.]

Have you considered a Hamburg mat filter? This is effectively a sheet of
filter sponge as high as the water level in the tank and of a width that
the entire tank volume can be passed through it once an hour at 10
cm/min linear flow rate (i.e. quite slowly). It is mounted either at one
side of the tank or across one of the back corners, creating a small
space which holds the pump, heater and any other bits of technology (or
use two half-sized filters in both corners with independent pump, heater
etc for redundancy).

The tank side of the mat can be covered with java moss or similar
plants, so that it becomes invisible to the observer. The water is
sucked through the mat by the pump into the enclosed space and returend
to the tank in a stream, which is used to agitate the water surface to
allow oxygen to dissolve. The denitrifying bacteria live in the pores of
the mat.

Advantage of this system is that is fully contained inside the tank, no
water hoses between tank and filter that can burst and flood your
appartment. Depending on how the outflow of the pump is arranged,
elimination of CO2 can be reduced considerably, obviously at the expense
of oxygen dissolution. No fishes, not even fry, can be sucked into the
filter. This system is cheap and simple, and has been used with
considerable success especially in large tanks.

To hold the mat in place, glue U-profiles (the sort used to hold cables
against a wall) with the flat side onto the glas of the tank.

[NetMax]

"Dr Engelbert Buxbaum" > wrote in message
...
> Trapper wrote:
>
>> [Modular filters in planted tetra tanks]
>> [I worried about w/d filters' outgassing power making CO2-injected
>> tanks difficult to maintain, and suggested use of modular system
>> with a fluidized bed biofilter, micron filter, UV sterilizer, heater
>> on my planned 125-gal tank instead of a w/d hodgepodge.]
>>
>> [I also mentioned CO2, peat/driftwood to get pH to 6 and softness to
>> discus-like levels.]
>
> Have you considered a Hamburg mat filter? This is effectively a sheet
> of
> filter sponge as high as the water level in the tank and of a width
> that
> the entire tank volume can be passed through it once an hour at 10
> cm/min linear flow rate (i.e. quite slowly). It is mounted either at
> one
> side of the tank or across one of the back corners, creating a small
> space which holds the pump, heater and any other bits of technology (or
> use two half-sized filters in both corners with independent pump,
> heater
> etc for redundancy).
>
> The tank side of the mat can be covered with java moss or similar
> plants, so that it becomes invisible to the observer. The water is
> sucked through the mat by the pump into the enclosed space and returend
> to the tank in a stream, which is used to agitate the water surface to
> allow oxygen to dissolve. The denitrifying bacteria live in the pores
> of
> the mat.
>
> Advantage of this system is that is fully contained inside the tank, no
> water hoses between tank and filter that can burst and flood your
> appartment. Depending on how the outflow of the pump is arranged,
> elimination of CO2 can be reduced considerably, obviously at the
> expense
> of oxygen dissolution. No fishes, not even fry, can be sucked into the
> filter. This system is cheap and simple, and has been used with
> considerable success especially in large tanks.
>
> To hold the mat in place, glue U-profiles (the sort used to hold cables
> against a wall) with the flat side onto the glas of the tank.

Perhaps the mat filter wouldn't satisfy Trapper's interest in
experimenting with a w/d filter, but I would strongly second the
suggestion to look into it otherwise. I've used mat filters very
effectively on tanks as small as 60g, and I don't doubt that they could
be applied to even smaller tanks. I've had 20g tanks using cylindrical
mats (with a powerhead pulling from the center) and I was quite impressed
with their operation. Powerheads are quite robust and fail-safe, and in
a power failure, your biological media is still underwater. No
manufacturer will really promote them as there is very little profit in
it, which means they are cheap to built (DIY).
--
www.NetMax.tk

[Trapper]

"NetMax" > wrote in message >...
> "Dr Engelbert Buxbaum" > wrote in message
> ...
> > Trapper wrote:
> >
[snip]
> > Have you considered a Hamburg mat filter? [Dr. Buxbaum describes same]
> > [snip]

> Perhaps the mat filter wouldn't satisfy Trapper's interest in
> experimenting with a w/d filter, but I would strongly second the
> suggestion to look into it otherwise.

NetMax guesses correctly. I have an obsession with W/D filtres, no
doubt.

My 75gal has been up and running for a while, relying on a Rena
FilStar XP3 for both biofiltration and to run my homebrew CO2 reactor.
No ammonia spike has yet happened, and the plants are really going
berserk. The fish load is low (about 9" of fish).


Over the weekend I did some experimentation with an overflow system,
etc.

HARDWARE:
set up an Amiracle overflow box, 10gal sump, and Rio 1700 pump to
constitute the core of my would-be external sump system. The plumbing
from the skimmer box was 1-inch tubing. Return from the Rio was 3/4"
tubing. I ran this setup for about a day and a half, keeping the pH
monitor and the heaters in the sump. My Rena Filstar XP3 remained in
the main tank, where it also runs my CO2 reactor.

QUESTIONS PRESENTED:
(1) Is it possible to run a w/d and still keep the tank's [CO2]
proper?
(2) Is sump heating effective?
(3) Is sump pH sensing effective?
(4) Is power-fail and siphon-fail failsafety achievable?

ANALYSIS:
(1) Yes. I had to tinker a bit to get this to work, but it
ultimately was possible. I did this by obstructing the 1" overflow
tube to restrict the flow rate into the sump, and also by making sure
the siphon tube was underwater in the sump. The idea was to minimize
sloshing of outflow water. I didn't really try it with a bona-fide
trickle filter going. It is clear that what agitation was not
eliminated did effect an outgassing of some degree, but, as I thought,
I was ultimately able to overpower it with my CO2 reactor.

(2) Sump heating did work, though I had to dial up the heaters a bit
to do it. This is not fundamentally different from having to tinker
with heaters in the main tank, save for the fact that we're talking
about 6" of submersion instead of 20". Much easier access to hardware
(a design goal fulfilled) and plus no heaters cluttering the tank.

(3) Sump pH sensing. This worked, in much the same way the sump
heating worked. The sensor reported a consistent 0.03-0.05 delta in
sensed pH versus immersion in the main tank. Two things emerge from
this: (a) that it'd be a pretty straightforward matter of calibration
to get the right setting on the pH monitor; and (b) the
CO2-dissipation capability of the overflow/siphon is calculable.

(4) Power-fail and siphon-fail failsafety are just a matter of
getting the right position of overflow box, return hoses, etc., and
cable-tying things into submission. I did this all without using
check valves, which I'll purchase befire I ever consider using the
system permanently.

CONCLUSION:
I answered these questions substantially to my satisfaction. I have
disconnected the system for now because I just wanted to cut my CO2
use, and mainly keep things simple during the week when I'm mostly
gone all day. The next incarnation of the system will likely differ
in some material respects:
(i) check valves employed, as noted above.
(ii) I'll try to get a smaller bulkhead fitting for the overflow box,
maybe going down to 3/4" or even smaller tubing, so as to reduce
"siphon slosh."
(iii) I'll have to design (or buy) a CO2 reactor that can work in the
sump under 6" of water. My current design goes up-and-down in about
15" of space (ugly!).
(iv) the sump made dosing and water changes easy.


> I've used mat filters very
> effectively on tanks as small as 60g, and I don't doubt that they could
> be applied to even smaller tanks. I've had 20g tanks using cylindrical
> mats (with a powerhead pulling from the center) and I was quite impressed
> with their operation. Powerheads are quite robust and fail-safe, and in
> a power failure, your biological media is still underwater. No
> manufacturer will really promote them as there is very little profit in
> it, which means they are cheap to built (DIY).

Good points, as usual.

Regards,
--Trapper

[NetMax]

"Trapper" > wrote in message
om...
> "NetMax" > wrote in message
> >...
>> "Dr Engelbert Buxbaum" > wrote in
>> message
>> ...
>> > Trapper wrote:
>> >
> [snip]
>> > Have you considered a Hamburg mat filter? [Dr. Buxbaum describes
>> > same]
>> > [snip]
>
>> Perhaps the mat filter wouldn't satisfy Trapper's interest in
>> experimenting with a w/d filter, but I would strongly second the
>> suggestion to look into it otherwise.
>
> NetMax guesses correctly. I have an obsession with W/D filtres, no
> doubt.
>
> My 75gal has been up and running for a while, relying on a Rena
> FilStar XP3 for both biofiltration and to run my homebrew CO2 reactor.
> No ammonia spike has yet happened, and the plants are really going
> berserk. The fish load is low (about 9" of fish).
>
>
> Over the weekend I did some experimentation with an overflow system,
> etc.
>
> HARDWARE:
> set up an Amiracle overflow box, 10gal sump, and Rio 1700 pump to
> constitute the core of my would-be external sump system. The plumbing
> from the skimmer box was 1-inch tubing. Return from the Rio was 3/4"
> tubing. I ran this setup for about a day and a half, keeping the pH
> monitor and the heaters in the sump. My Rena Filstar XP3 remained in
> the main tank, where it also runs my CO2 reactor.
>
> QUESTIONS PRESENTED:
> (1) Is it possible to run a w/d and still keep the tank's [CO2]
> proper?
> (2) Is sump heating effective?
> (3) Is sump pH sensing effective?
> (4) Is power-fail and siphon-fail failsafety achievable?
>
> ANALYSIS:
> (1) Yes. I had to tinker a bit to get this to work, but it
> ultimately was possible. I did this by obstructing the 1" overflow
> tube to restrict the flow rate into the sump, and also by making sure
> the siphon tube was underwater in the sump. The idea was to minimize
> sloshing of outflow water. I didn't really try it with a bona-fide
> trickle filter going. It is clear that what agitation was not
> eliminated did effect an outgassing of some degree, but, as I thought,
> I was ultimately able to overpower it with my CO2 reactor.
>
> (2) Sump heating did work, though I had to dial up the heaters a bit
> to do it. This is not fundamentally different from having to tinker
> with heaters in the main tank, save for the fact that we're talking
> about 6" of submersion instead of 20". Much easier access to hardware
> (a design goal fulfilled) and plus no heaters cluttering the tank.
>
> (3) Sump pH sensing. This worked, in much the same way the sump
> heating worked. The sensor reported a consistent 0.03-0.05 delta in
> sensed pH versus immersion in the main tank. Two things emerge from
> this: (a) that it'd be a pretty straightforward matter of calibration
> to get the right setting on the pH monitor; and (b) the
> CO2-dissipation capability of the overflow/siphon is calculable.
>
> (4) Power-fail and siphon-fail failsafety are just a matter of
> getting the right position of overflow box, return hoses, etc., and
> cable-tying things into submission. I did this all without using
> check valves, which I'll purchase befire I ever consider using the
> system permanently.
>
> CONCLUSION:
> I answered these questions substantially to my satisfaction. I have
> disconnected the system for now because I just wanted to cut my CO2
> use, and mainly keep things simple during the week when I'm mostly
> gone all day. The next incarnation of the system will likely differ
> in some material respects:
> (i) check valves employed, as noted above.
> (ii) I'll try to get a smaller bulkhead fitting for the overflow box,
> maybe going down to 3/4" or even smaller tubing, so as to reduce
> "siphon slosh."
> (iii) I'll have to design (or buy) a CO2 reactor that can work in the
> sump under 6" of water. My current design goes up-and-down in about
> 15" of space (ugly!).
> (iv) the sump made dosing and water changes easy.


Thanks for the update, very educational :o)
--
www.NetMax.tk