The missing factor???!!!

[hadjici2]

ok people,

I have:

1. pH 6.8
2. kH 5
3. 5 ppm nitrate
4. 20 ppm potassium
5. Have not added magnesium
6. Have not added phosphate
7. 75 watts fluorescent lights over a 30 gallon tank
8. Trace elements added by adding Tropiflora (Tetra)
9. 2 mollies so I guess phosphates added by feeding

The tank has a very old substrate. The plants are not doing well and more specificaly Valisneria isn't growing fast and has yellow leaves. Also alot of green hair algae. I am using the EI method...

What is the limiting factor?
How do I know how much of the stuff I added is being used so as to add more?
Will I see a difference the next day so I can see its working?

My tank diary:

12 Aug 04 - Added DIY CO2, added one teaspoon bicarbonate soda, kH from 4 is now 5, pH is 6.8 - 7
Effect: none

13 Aug 04 - Added 5 ml from a KNO3 mixture (4 teaspoons in 120 ml gives 1 ppm nitrate per ml) thus added 5 ppm of nitrate
Added 1 teaspoon Epsom Salt thus added 4.69 ppm Magnesium
Effect: bubles underneath leaves indicate photosynthesis


14 Aug 04 - Added 35 ml of K2SO4 mixture (8 teaspoons K2SO4 in 400 ml gives 0.47 ppm per ml)
Effect: bubles underneath leaves indicate photosynthesis

15 Aug 04 - Added 5 ml of Microplex mixture (1 tablespoon Microplex in 250 ml of water)
Effect: bubles underneath leaves indicate photosynthesis but now at a lower rate

16 Aug 04 - Added 5 ml from a KNO3 mixture
Lowered the lights
pH 7
Effect: cannot see fast growth but leaves of plants are shiny

17 Aug 04 - Added 35 ml of K2SO4 mixture

18 Aug 04 - Nothing done
Effect: Hair algae

19 Aug 04 - CO2 is running out of ingredients so pH increase thus less CO2
Effect: Hair algae

20 Aug 04 - Added another bottle of CO2
50 % water change
Added 35 ml of K2SO4 mixture
Added 4 ml from a KNO3 mixture (4 instead of 5 ml so as to account for the nitrate produced by fish in the tank)
Effect: none seen

21 Aug 04 - Added Tropiflora
Effect: yellowish leaves, tank may even seem worse

 

[happychem]

If you're not adding PO4, that's the most likely culprit. Without PO4, plants cannot make use of the other nutrients properly. All things in balance.

Another possibility is that your substrate needs cleaning. A good thorough cleaning of an old, undisturbed substrate can help to remove the excess of detritus that's built up.

 

[hadjici2]

Another possibility is that your substrate needs cleaning. A good thorough cleaning of an old, undisturbed substrate can help to remove the excess of detritus that's built up.

but my substrate also contains layers of sand (probably sand or maybe something else like sand) and it would disturb the whole bacteria colonies....

 

[midiamin]

Get a Gravel Vac from your lfs. They will tell you how to operate it also.

thePlantMan cometh................

 

[midiamin]

Gravel Vac

Get a Gravel Vac from your lfs. They will tell you how to operate it also.

thePlantMan cometh................

 

[happychem]

but my substrate also contains layers of sand (probably sand or maybe something else like sand) and it would disturb the whole bacteria colonies....

I'm somewhat confused by your post, didn't you set this tank up? What is the substrate?

No, vacuuming will not disturb the bacterial colonies, but it will clear out the tons of mulm that has built up in your very old substrate.

 

[djlen]

I have:

1. pH 6.8 - OK
2. kH 5 - OK
3. 5 ppm nitrate - I suggest pushing it up to 10ppm - 15ppm
4. 20 ppm potassium - How are you measuring this?
5. Have not added magnesium - I suggest 1.5 tsp. after water change
6. Have not added phosphate - I suggest 10 drops of Fleets Enema to push
for 1.5 - 2.0ppm. If 10 drops don't yield at least 1.5 add 5 more.
7. 75 watts fluorescent lights over a 30 gallon tank - OK
8. Trace elements added by adding Tropiflora (Tetra) - How/how often, are you dosing this?
9. 2 mollies so I guess phosphates added by feeding - huh?

Sounds like nutrient deficiencies could be your issues, but the 'sand' thing could also be an issue as well if it's real fine sand and been in there a long time.
Keep your nutrient levels up. Dose Macros after water change. Test for content of N and P to see what your plants are using. In my case P supplementation is usually needed at mid week. Traces should, IMO be dosed all week long.
The way you control your tank's parameters is a 30 - 50% water change to re-set at week's end. Then start over again.
To keep your DIY CO2 ppm up and consistent, run two 2-ltr. bottles and change off one of them every week to maintain flow. Don't wait for a drop to start getting up another bottle. Inconsistent gas flow can contribute to issues like you are experiencing.

Len