Re: Stalled tank/Plants not photosynthisizing?

[Thomas Barr <tcbiii at earthlink_net>]

> From: RobHags at aol_com
> Subject: Plants not photosynthisizing?
> 
> Hello all,
> I don't want to sound long winded so I'll get right to the point. I have a 75
> gallon tank that is heavily planted. Light source is 2 175 watt metal
> halides.Ph is 6.85 .Temp. is 82. GH is 5. kh is 3. Pressurized co2 through a
> reactor at 3 bubbles every 5 seconds. Moderate fish load so fertilizer is
> kept to a minimum. Phosphate and nitrate are well within normal range
> Substrate is plain gravel over laterite.
> In the morning after the lights come on I always used to see tons of little
> bubbles on the plant leaves. Now I see almost none. Plants still seem ok but
> cabomba and other simmilar plants are elongated between leaf nodes. Growth
> has definetly slowed.Any help would be greatly appreciated!!!

CO2,Check the KH again and check the pH in morning when the lights come on
and when they go off at night. Compare to the chart(pH/KH/CO2).
Next check the NO3 and K. If you have no kit, do a large water change and
add KNO3(1/2 teaspoon will add about 5ppm). Even with moderate fish load,
350 w of MH on a 75 is a lot of light. NO3 is likely gone. PO4 is another.
Check stuff over again. If in doubt, do a water change and add the nutrients
back afterwards. This will reset the tank and take the guess which single or
combination of nutrients you are missing.

Regards, 
Tom Barr