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Re: Discus plant filter tank

> Question/issue:
> There is plenty of information out there about the redfield ratio. Higher
> N: P values promote higher plants and green algae, lower N:P favours
> especially blue-greens ,16 to 1 is indicated somewhere as a good benchmark
> for our aquariums and most plants.

No, this is a phytoplankton ratio for the seas.
FW algae are 14:1
Aquatic plants are 10:1

 I took some measurements and as well
> followed the "estimative index" approach described by Tom Barr ( is his
> name in every mail ? )  . I assume that, in my "almost  no algae problems "
> situation, using  above described inputs, I must be relatively close to
> good N:P values. And  now I have introduced a terrestrial plant filter. My
> question is how this may impact the nurient ratios.
> What kind of nutrients does a terrestrial plant filter use?  Do terrestrial
> plants consume N and P in similar ratios to aquatic plants?  Are
> terrestrial plants better at consuming P than N or oppposite ?  far better?
> do terrestrials use atmospheric N instead of NO3?

No, only diazeotrophic bacteria will use N2.
Nothing else does.
Azolla, Beans, etc have Anabeana or Rhizobium symbiosis etc.
Generally the plants will be close to the ratio of aquatic plants.

The ratio is not going to make or break your tank. I'm not sure I'd give the
ratio regarding some dosing notion much credence anyway. Plants will take up
more than the need of PO4/NO3 etc.

Now the plant filter is
> there,  I hope to be able to increase my fish bio-mass without compromising
> too much on algae issues.

Yes, but why add so many fish to some little box?
If you want more fish, get more tank.

> If the plant filter only takes the N out of the
> water I am facing a problem and will need to dose a lot of N otherwise  P
> will build up , if a plant filter takes a good N:P ratio out of the water I
> may be OK.

The terrestrials will remove pretty much the same things.

 If the plant filter takes mainly P, I am a happy man since al
> lot of the  the P of fish foods would be absorbed easily.
> If N and P are dosed only via fish food and water changes, (all other
> nutrients are supplied chemically):  Does fish food give a reasonable N: P
> balance? 

No. At low light maybe.
Fish food needs converted into NO3 also.
Even if you have lots of filtration/plants etc, if you keep adding more and
more fish the NH4 will be high enough to induce an algae bloom.

Adding more fish to supply the N needs has limits.
Keep a reasonable amount of fish.

Give them a good home, not a crowded city.

Fish food doesn't add enough PO4.

> or can I assume fish food to add too much of one . ( daphnia and
> mosquito larvae and dry flakes, later I want to be able to use  beefheart
> recipes ) Since I had reduced planth growth when reducing feeding I expect
> this plant filter may compete too much with my aquarium plants .

Perhaps but if you dose regularly it won't matter much. The plant filter is
a back up if the CO2 goes south or you forget to dose something.

 So is
> there a risk of over filtering by using terrestrial plants? or would a
> terrestrial plant filter throw off the balance by filtering out too much of
> N or P that is introduced by increased feeding?

It's pretty much like adding more aquatic plants to a tank.
> I have put quite some fish in this tank for one reason only: I want a
> planted discus tank eventually ( Have experience with discus and plants ) I
> figured that if I load that tank with plenty of fish and I can manage it
> without algae, I can assume the same biomass in discus can replace the
> current stocking level safely without algae.  I want this heavily planted +
> philodendron filter tank  to support a family of 4-5 or may be 6 adult
> discus + some small algae eating goodies .Do I stand a chance?

Why not do this: don't stuff your fish to the gills except when they are
small, after 3-4 inches feed once a day etc what they can eat in 5 minutes
etc. My fish did fine and grew quite large. I also had KH 5.5 GH 9 temp 82
did 50%+ weekly changes etc. Get over all the prime breeding advice and
settle for slightly less than "perfect" Discus breeding conditions. They
will do quite well.
> ( current fish in the 75 G : 15 full grown congo tetras, pair of kribs, 15
> red phantoms, 8 rummynose tetras, 5 full grown SAE , some AFF and some
> otto's, some Yamato-ebi japanese swamp shrimps )

Shrimps will be food for them later.
I'd put no more than 5 adults in the tank,
15 phantoms, get some small SAE's, otto's are good, AFF=?, I'd add perhaps a
few cories. Congo's, Kribs etc I'd lose.

I'd have either all phantoms or all rummy's.

Tom Barr

> thanks a lot
> suisoman Dirk