[APD] Re: More fish die off

[Michael Skidmore <mskidmore at alamedanet_net>]

Cardinals tetra can be very hardy fish and live up to 3-4 yrs (10 
years from one report)  in  tanks that take into account their needs. 
What works best for full tilt plant growth doesn't work for 
cardinals, especially newly bought ones.

I lost two schools of Cardinals back to back with water changes. I 
have a heavily planted tank, 3 wpg,  pressurized CO2, usually 4-5 kH 
and 7-9 gH, temp 82 for discus and loaches. I follow many 
recommendations here and do 50% water changes every 5 days. The 
plants grow fast and pretty well.  Our city tap water is moderately 
soft in winter but very soft (in spring/ summer)  lately around 1 kH 
and under 1 gH. It does contain choramines.  So when I water change I 
use a python to temperature match and I add usually 1 tsp baking soda 
(in winter) to the incoming 30 gallons or so of tap water. I also add 
1 tbs of Amquel (old formula) for the Cl+ choramines.  So really 
nothing should  fluctuate as I do the water change. Then at the start 
of summer as the snow melt started and EBMUD (water co) mixed in well 
water the  water hardness halved. Since I was still doing 1 tsp 
baking soda , I was having kH drops of 2 degrees, with no change in 
temps or pH (it's is on a SMS 122 controller at 6.8)

Just this change in hardness was enough to kill the cardinals I 
think. I lost half the school of 30 after 1st water change and the 
remainder after the second. Bought replacements and repeated same 
mistake with another 20. I didn't notice how much the tap water had 
softened and was buying cardinals just as EBMUD changed to the summer 
mix. I am currently adding 2 tsp baking soda and 1/8 tsp epsom salt 
(twice what I needed just 3 months ago.)

I have since got 20 new cardinals and setup in their own tank which 
is low light, no CO2, 82 F . They get only 25% water changes biweekly 
(6 gal:25 gal) but I do not do any hardness adjustments. I just left 
the tap water soft  (0.9 kH and about 1-2 gH)  as is. I do test 
before and after. All I do to that tank is use Seachem acid buffer to 
drop pH to 6.4 and I add a few grains to a 3 gal bucket to drop 
incoming water pH from 7.8-8.2 to around low 6's.  The 2 year old 
huge  Java fern (regular variety) in the tank isn't doing very well 
after 6 weeks of this it was grown in in another tank (76 F under 1 
wpg with 2 15W 5500k  normal florescent tubes, low pH, but harder 
water ) , but the crypts, najas, and hornwort are growing ok.

I think I am burning the java fern since I put in a Smartlite 
retrofit kit in the Eclispe 2 hood to add a reflector and switch to 
compact florescent bulbs. It came with a 10,000K and blue actinic 
dual 32W bulb. I planned on replacing it with a 6700K but I really 
like how it brings out the cardinal's colors. That maybe isn't going 
to work much longer.

So take home message, be cautious when making water changes with 
Cardinals and match the before and after closely.

As I pointed out to Tom Barr a few weeks ago "FAILURE: Maybe your 
(my) only purpose in life is to serve as a warning to others"
--
_________________________________________________________
Michael O. Skidmore
Alameda CA
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