[aquasox]

Hi,

Finally got these suckers growing with CO2 (Cryptocoryne wendtii "Tropica" and Crypt X willisii).

Tank parameters:
38 gallon

pH< 6
kH<2
gH< 20 ppm
light 2.5 Wpg
CO2 ~1bpm

Dosing as per PPS PRO

I want to do a water change to clean things up a bit. How much Ca can I add at a time without shocking the crypts. Also how much water can I take out without melting them?Thanks

 

[HeyPK]

Both those crypts do pretty well in hard water. I wouldn't think that 50% water changes would bother them, but don't do the water changes more than once a week.

 

[aquasox]

Plan on 50% WC's on frequency of 1-2 times per mo....so I'm OK there....how many ppm Ca should I add?? Is 5 ppm OK? (I'm guessing because you said they handle hard water pretty well.)


...the water is very soft and Ca reads at the lowest level the test kit goes. I think the crypts melted before because of fluctuating CO2 levels, but I don't want to chance it by adding to much Ca.

 

[Kai Witte]

Why do you want to add any Ca at all? Unless you wish to keep plants and/or critters which need high Ca levels, I'd leave it as is (lots of organisms which prefer soft water)...

Crypts can be a little sensitive to high/fluctuating CO2 levels but with soft water you don't need that much anyway.

 

[aquasox]

I thought it might be a good idea since I'm adding Mg...and I didn't plan on doing many water changes...I imagine that the Ca would eventually become exhausted if I didn't replace some of it...I didn't plan on adding a heck of a lot of Ca...just a little bit.

I guess I could get enough Ca from the water change alone...perhaps the statement "if it ain't broke don't fix it" applies

 

[HeyPK]

High CO2 combined with low light---1 watt T12 fluorescent per gallon or less--- can cause melting in submersed crypts. Give them 3 watts T12 fluorescent per gallon, and there will be no melting with the CO2. I wouldn't worry about calcium being too high with these Sri Lankan crypts. All plants need calcium, and unless you produce some sort of record high level of calcium, you shouldn't have to worry.