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PO4 heresy
Tomm Barr wrote in response to my post (PO4 supplimentation):
> Rather than add more NO3 and P why not add more food? Over fed if needed.
> Using Flourite you also have less need for the Fe. Also..... don't you add
> jobes to the gravel also? The palm ones?
You may remember I inadvertantly placed 8 Jobes sticks in my substrate
before I realized that 8 stick was considered a lot. Fearful of a crash, I
watched my E. bleheri outgrow my tank in about a month (the Frankenstein
monster), but other than that suffered no direct ill effects. That was 8
months ago and figuring I had lucked out I haven't added more Jobes sticks
since. And you're right - I supplement mostly with TMG and have little need
for additional Fe except in very tiny amounts once in awhile when the water
tests out to 0.0ppm.
> So you have to test for yet another element to use this system(PO4 and
NO3)?
> I know for a fact I have run some PO4 deficient tanks and I know what they
> look like. Algae ain't a sign of it BTW!!! Certainly not BBA nor GSA.
Yes, I watch both NO3 and PO4. As long as I continue to hit the sweet spot
they both get consumed rapidly. When I miss the right proportion one way or
the other the tank has extra nutrients floating around and there's almost
always a negative impact. Whether algae growth is a direct or indirect
result, it almost always seems to occur when I've missed that golden
proportion. Believe me when I say I'm no scientist nor do I claim to run
experiments in a closed system. I simply play with my aquarium on a
frequent basis and when I enjoy excellent results - or extremely poor
results - I report them here!
> I agree that plants need some PO4 though.......enough to crash
> your tank or cause algae? Not IMO. The Theory of PO4 limited tank is
> still a good one IMO.
I like the idea of supplementing enough PO4 to feed the plants, but still
using a small enough amount that the tanks runs out of PO4 before it runs
out of anything else. During a good week tank remains phosphate-limited
even while adding phosphate on a regular basis! I think Karen Randall's
recent post indicating her excellent results using tapwater with measurable
PO4 bear this out.
> I use both some times(the palm and the regular 15/15/15). You can add the
> PO4 in the form you described but I think the bacteria will cycle it into
> your tank for the plants eventual use just as well and perhaps better than
> adding it to the water column in an inorganic form. You risk algae more
> using the water column method perhaps............... but we also use to
say
> this about NO3 and Diana W's book used Fe as the limiting element in the
> column etc as the cause.
I've come to realize, in my limited experience, that feeding the same
nutrients in the substrate and in the water column have different effects on
the tank as a whole. Seasonal changes may come to bear as well (SF water
has a much lower KH in the winter). I've found that both ways in moderation
work better for me than relying on only one form of supplementation.
> Again, BALANCE, is the key.
No argument there, Tom! It seems that the better balanced an aquarium is
the more abuse it can absorb before seeing a negative effect.
-------------------------------------
michael rubin
michael at rubinworld_com
http://www.rubinworld.com/aquarium.htm