lighting question

[new2tanks]

my new starter kit came with 2 fluorscent bulbs-4200K (sun-glo)and 18000K(aqua-glo) both 15 watts each.ive heard that plants need around 6700 K
so does this mean that my plants wont grow.or can i use these and just replace them with 6700k bulbs when its time to replace?
this for a 20g (high stle ) tank. and i wanted to grow low light to med light plants...
thanks.

[djlen]

Are the lights you have CF(compact fluorescent) or NO (normal output) bulbs? At 15 watts, they're probably NO.
Not a lot of light but OK for the type plants you want to grow.
If the light in the tank looks OK to you then I'd keep them and switch to two 6700K in about a year when they'll need replacing.
18000K is a very very blue light, especially for fresh water tanks, but if you find that it's not doing the job you could switch it. You received a really weird combo there in the 4200/18000 kelvins.
Once again, if you like the look plant some plants and see how they respond. Plants are not picky about color. Kelvin rating is more for the human eye.

Len

[new2tanks]

how to figure out if they are compact fluorscent or normal output?
they are t8's i believe.
thanks for your help though, at 1.5 wpg, i know its low light but i think its okay with low to med light plants.

[djlen]

Yes, they are NO. Don't forget to replace them at 8 - 10 months. They tend to lose a lot of brightness in that time. You should see a marked difference in brightness after replacement.
Cryptocoryne, Anubia, Tiger Lotus, E. Tenellus, Pennywort should all do pretty well for you under that lighting.

Len

[Hound]

Just for reference, but the wal-marts near me have 6500k GE t-8 bulbs in the 15w 18" configuration. Can't remember how much atm, but I know it's cheaper than my lfs / lps.

[new2tanks]

thanks hound and djlen!