Re: PMDD/CO2 etc

[Thomas Barr <tcbiii at earthlink_net>]

> I would have loved to buy a compressed bottle system but I had a budget.
> When I researched this aquatic plant hobby there was conflicting opinion
> regarding substrate heating. I figured it would be a lot harder to add
> cables later so I chose them over high tech CO2. As for the R/O filter
> I've had that for 10 years - used it with a salt water tank. My tap
> water is on a softener (salt type) so I don't use straight tap water.
> I hear what you're saying though - consistent CO2 = more stable
> conditions. I've known that is a shortfall with my setup which is why I
> change yeast mixture weekly. I guess I should start looking around for a
> CO2 bottle and regulator. BTW, do you use a PH controller on your system
> or is that just a luxury item?

Luxury item big time. pH monitor is very nice to have to check your CO2 via
the ph/KH chart.
Both items(Gas CO2 and pH monitors) are two things you'll be glad you got.
You certainly won't regret them and the gas will be much nicer/easier for
you. You'll only mess with the nutrients/water changes/pruning gardening
aspects and the CO2 will be like the lighting, you might mess with it once a
year etc. 
 
>> I don't mix the the PMDD in liquid except for the traces. I add the KNO3
>> dry, 1/4 teaspoon 2-3x a week is about right for your tank. 50% water
>> changes weekly, if you want to make that much RO. Many folks don't, another
>> reason not to use RO water, pain in the a for doing water changes then you
>> have add the RO right etc.
>> K2SO4 also can be added at 1/4 teaspoon weekly. PO4 additions can help if
>> the CO2 is good and the PO4 out of the tap is very low etc.
> 
> Wow, 50% weekly water changes? I must have missed something somewhere -
> I thought 20-25% per week was considered good.

Doesn't take but 3-4 minutes longer if you use the tap. Less if you have the
"Alan high speed system". Some folks do the lesser amounts with decent
success, but your talking about not spending $ on test kits etc. This is a
good way to get around that. A good level/range of NO3 is the key, not
guessing and hoping. Once it's(NO3) too high/too low it's too late=> algae
is already starting.

> If the plants are
> consuming the majority of the Nitrogen in the tank what are we
> accomplishing by removing 50% of the water every week?

You don't want to test for each nutrient each week and carefully add and
make sure you have the right balance each time?
By removing the water you re-set the tank each week and add the nutrients
back. You can guesstimate what the tap water is and add known amounts of
KNO3/traces/K2SO4/KH2PO4 back afterwards.
This removes most of the error you might have done on dosing and guessing
what the plants may or may not have taken up during the week.
It also eliminate the need for so much testing(it's easier to do weekly
large water changes) and test kit inaccuracies.
It removes any unknowns that may  build up in your tank. 50% is a good
amount that is easy to gauge what your make up water has in it.

Then you guess about what your tank "eats" through the week till your next
water change. Re set it again. Nothing gets too far out of balance nutrient
wise this way.  

The nutrients are cheap, the tap water is cheap and the system is simple and
quick. Most folks can spend an hour on the weekend etc to do the water
change etc. Dosing etc after and during the week is only a minute etc/like
feeding the fish. 
If the CO2 is good, the water change+ nutrients are added afterwards, folks
have only mild unrelated algae-nutrient issues. These can be dealt with by
herbivores, manual cleanings, pruning, slight tweaking of their nutrient
mixes etc.
Regards, 
Tom Barr