more questions!

yme

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Nov 30, 2005
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hi again!

Your advice following, I lowered my pH by 0.1 and increased my PO4 addition to 0.3 mg/l/day. I already see results that I want to discuss.

First of all my settings (it may help)

Tank: 100x40x40
Pomp: eheim professional (containing just white foam)
CO2: pressurized, administration by wooden airstone
Substrate: amtra plant depot (1.5 years old)
Light (30 watt per TL):
1x Philips TL 840 (middle): 13.00-23.00
1x Philips TL 830 (middle): 13.30-22.30
1x Philips TL 830: 19.00-22.00
1x Philips TL 840: 19.00-22.00
1x Philips TL 840: 19.00-22.00
liquid fertilzer: 3-4x/week 8 ml flourish, 3-4x/week 8 ml flourish iron
pH: 6.3 (now 6.3 again)
KH: 4.0
GH: 6
PO4: 0.3 mg/l/day (the actual PO4 level in the tank is quite low, 0.5-1 mg/l)
NO3: 2 mg/l/day (NO3 levels are rising during the week, 17 mg/l directly after waterchange, to 25 mg/l after 7 days)
Conductivity: 480 µS
Water change: 60 litres per week, 30 litres of RO water and 30 litres of tap water (pH 8, KH 7-8, GH 8, 660 µS, NO3 10, PO4 0)


I saw that my shrimps were near the surface or even above. Really abnormal behaviour! I also saw one dead shrimp. My guess is that the decrease in pH from 6.4 to 6.3 was too much. too much CO2. I didn´t degass my aquariumwater for 24 hours yet, but the pH of the sample that I took from the aquarium this morning is now (6 hours later) at a pH of 7.6. So it is more than one point, suggesting that I have enough CO2 in the tank even at a pH of 6.4 do you agree?

The other thing that I saw (and really liked!) can best be explained by a drawing.

ALG-CO2.JPG


So I see that the CO2 bubbles are pushed by the current of the filter outlet towards the front glass. By eye, I can see the bubbles reach the glass. the complete left side of the front glass is in direct contact with the bubbles. The right side is not. Now I see is that the left side is free of algae while the right side gets single stranded fuzz algae. (additional info; the outlet of the powerhead is not directed towards the glass, so I think there is less current near the front glass at the right site of the tank).
Now I wonder: WHY? Is it the higher CO2 concentration on the left side of the tank (not measurable by my pH meter), is it the stronger current or is it a combination of both?
To test this, I replaced the powerhead in such a way the current from the powerhead reaches the glass at the same angle as the current from the filter outlet. we will see!!

For the nitrate and phosphate: 0.2 mg/l/day nitrate is for the moment enough. during the week the level is still rising. 0.3 mg/day phosphate does not provide enough PO4 for a stable level: the PO4 levels are still dropping during the week. Should I increase the PO4 addition even more? (values are measured by photospectrometer)

One other thing that I wanted to ask is that the new leaves of the proserpinaca palustris are a bit small and especially in the morning they are curled. The curling is less in the evening? What is causing this?

greets,

yme
 

VaughnH

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Re: more questions!

A PH decrease of about 1.0 from degassed to whatever is in the tank, means 30-40 ppm of CO2 in the water. But, if the decrease is 1.3, those CO2 numbers double! So, obviously you have to be careful not to go more than a 1.1 decrease, or the fish will suffer. I think the best way to do this is to increase CO2 just a bit each day, until you get the 1.0 decrease, then use the bubble rate you see at this time as the bubble rate you want to maintain. If you try to control the CO2 to the right level using a PH controller, all it takes is a KH drop or a reduction in PH contribution from something else, other than CO2, in the water and you have too much CO2.
 

Tom Barr

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Jan 23, 2005
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Re: more questions!

The algae forming on the one side is namely from less current, not nutrients.

You will sometimes get some algae formation when you change some nutrient levels, generally not a lot, ecologically, these can be large shifts over time, but not in our tanks.

They tend to be temporary in nature and after a week or two are gone away with good maintenance.

I would add more PO4.
Like 2-3ppm should be what you measure in the tank.
That will reduce glass algae.

CO2 seems high enough.
Add another 1/4 teaspoon 2x a week of MgSO4(Epsom salt)

That should about do it.
NO3's seem decent and about right.
I assume you are using KNO3 for the dosing of NO3.




Regards,
Tom Barr
 

yme

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Nov 30, 2005
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Re: more questions!

thanks!

I indeed add KNO3 and kH2PO4.

I guess I forgot one important detail... Before the change of pH and PO4 I had fuzz algae on the glass everywhere. So it is actual a big improvement! (in my opion anyway). However, I didn´t cleanup my filter, so the current was the same "as always". And still I see a decrease in algae growth on the left side. Thus, I don´t think it is just the current. From your answer about the PO4 level I think I can conclude that the decrease of algae growth is due to the increase in PO4.

greets,

yme
 

Tom Barr

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Jan 23, 2005
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Re: more questions!

Well , have a little patience if you had a lot of algae prior, things will take a little time to get going, but as long as there is an upwards direction in improvement, things are doing well.

Generally, responses are fairly quick with algae, a few days at most for most species.

Plants sometimes can bounce back in a few hours to a few days/1-2 weeks.

Just stay on top of the algae, clean often, and maintain enough nutrients, things should settle down good and you should have less algae and better plants growth.


Regards,
Tom Barr