KH READING AND BUBBLE ON WATER SURFACE

[green plant]

Tank size : 36" x 30" x 24"
Gravel : average 4" thickness.
Just change water about 40%

1. KH problem
I have been adding soda, 2 tea spoon to boost the KH level by 1.6. Have already add 2 tea spoon of SODA before the water change, but te reading seems to indicate less than 1 KH level.
Is it normal?
By the how do we compute the water volumn? Do we need to less out the gravel ?

2. Water bubble on water surface.
Notice there are some bubbles on the water surface.
What cause it?

3. Surface skimmer
Have not install a surface skimmer yet. Would like to know how to prevent the fish food from been drawn into the filter by the surface skimmer.

[PeterGwee]

1)1 tsp of baking soda would give you a KH of 4 for 50l of water. For your case, 1.6 is a bit anal..why not 2dKH? For 2 dKH, go for 4 tsp. (I hope you got the right stuff...baking soda..not baking powder.)

[chrissia]

1. You should add after water change not before. Test it a day after. Less out the gravel would be more accurate.

2.There's probably an oil film on the water surface which traps your co2 or o2.

3.To rid the oil film, get a couple of guppy, platies or mollies. Save the $ on surface skimmer.