Fernando wrote:
Hi,

There are three types of plants
-Heteranthera zosterifolia: grows well depending on the zones they are
planted
-Limnophila sessiliflora: most of them seem weak and short, except
from one, and have many ramifications, growing more horizontally than
vertically...
-Lemma minor: a few that came with another plant

I planted "one" of each of the first two, they came in little packs.

Light is "aqua-glo" brand, 15W and 18 inches (tube).

Substrate is gravel, i don't use CO2 injection or extra nutrients and
don't test phosphates, only NH3, NO2, NO3.

Algae are filamented green ones, like little hairs.

I do 20-25% water changes weekly, although i've done some extra ones
this week to reduce high nitrates.

Not all of the guppies are grown, there could be about 20 with more
than two months old.

Filamented green algae, if it's fuzzy with very short hairs, is good
food for baby guppies. Tiny organisms like paramecia grow in the algae
and the guppies eat those too. You've probably noticed them picking at
it. So some is good to have in your tank. If you can reduce the
stocking level in your tank, you could add a bristlenose pleco
(Ancistrus spp.) or three or four Otocinclus spp. to help eat the algae.
Ancistrus are very fond of the fuzzy green stuff. Ancistrus and
Otocinclus require a piece of uncoated driftwood to chew on to obtain
necessary dietary fiber.

Mystery snails (Pomacea bridgesii) or ramshorn snails (Planorbus
corneus) are also good algae eaters, as are Japanese shrimp (Caridina
japonica). You can learn to tell the non-plant eating mystery snails
from the plant eaters at applesnail.net. Snails and shrimp will have
less impact on your biofilter and nitrates than fish, but also eat less
algae.

15 watts of light over a 17 gallon tank is not enough light for
Limnophila and I'm surprised you can grow Heteranthera. Under 1 watt
per gallon is considered low lighting when you look at aquatic plant
profiles. Aqua-glo is a poor spectrum for plants too - the light looks
purplish, right? Lemma will further reduce the light reaching your
plants, so net it out as it starts to grow too much.

I'd suggest you switch your bulb for a full spectrum "daylight" bulb
(5500K to 6700K color temperature) and get some plants better suited to
low light. You're not going to get a huge reduction in nitrates without
high lighting and CO2, but more plants will certainly help. Java moss
(Vesicularia dubyana), Java fern (Microsorium spp.), Anubias spp. and
Cryptocoryne spp. are all good plants for low light.

For the Cryptocorynes, since you have plain gravel, get a fertilizer
tablet to put in the gravel at the roots of each plant. It should have
iron and potash, but no nitrogen or phosphorus. Also, if you end up
with lot of plants actively growing, start using an iron fertilizer like
Tetra FloraPride or Seachem Flourish with iron.

You're still going to need frequent water changes as the guppies grow,
but maybe these suggestions will help some.

--
Elaine T __
http://eethomp.com/fish.html '__
rec.aquaria.* FAQ http://faq.thekrib.com