Re: mega dosing

[Thomas Barr <tcbiii at earthlink_net>]

> This is a 29 gallon with 2x 55w compacts. I don't know
> what higher than normal is for you, but I spike the
> N03- up to 20 or 25ppm and the P to a few ppm before a
> 60% water change the next day.

That's pretty much what I've been doing.

> I notice a slight
> increase in green algae on the front glass but
> otherwise things are kosher (I use the front pane of
> glass quite a lot for gauging nutrient conditions in a
> given setup.) This spiking seems to be helping a
> little with the lean-ish growth I've been seeing.

I have not had the green stuff on the glass. If the tank was not so full of
plants, the CO2 was a bit low, etc, then I would.
 
> I think that instinctively wanting to keep the tank
> leaner-running due to the high light might be
> detrimental (trying to be intuitive and anticipate
> excess under strong light). In fact, maybe the
> opposite is necessary. Richer conditions than would
> seem unreasonable at first for higher-light tanks may
> be needed for strong growth. Keeping N/P "just
> measurable" [or on the lean side] might not be good
> enough. 
> 
> Erik Leung
> http://www.e-aquaria.com

More light = more nutrients, more uptake. But...
But..........rather than the mega dosing approach, more frequent dosing is
all that's needed.

I've done fine with every other day or 2-3x a week. 2x a week is not enough
for my lighting values. But 2x a week will get me by without too much issue.

But with 3x a week dosing, I still do the mega dose the night before I do
the water change so it's about 12-18 hours before I do the water change(1st
day). I don't dose for 3 days after the water change(4rd day), then another
2 days later(the 6th day) and then the mega dose again the night before(7
1/2th day).

I think the mega dose really gives a nice shock that helps the plants while
hurts the algae is many cases(the young spores) from the coming water
change. Plants can load up but these reserves for things like K, PO4, NO3
don't last that long IMO.

Another aspect is the amount of NH4 produced in the tank. I'd say more is
produce as the week goes on. The water change removes the "food" for the
critters like algae, dead plant matter, fish water etc. The NH4 is nearly
impossible to measure.

It is simply recycled back into the system and the uptake is too fast to
measure it. When this recycling breaks down, algae appears. O2 seems to
foster this cycling also(think about these O2 consuming critters/bacteria
etc).  

Whether this plays a role in leaner tanks or not is debatable. But NH4
additions from critters I believe helps tanks a fair amount and is
underestimated since it's recycled so rapidly as it's being produced. Too
hard to measure with kits etc. NO3 as the sole source is great, but some NH4
a very low levels is sure to help some plants.

 
Regards, 
Tom Barr