ORP in the freshwater tank

[mak]

Hello everyone,

I'm wondering if ORP is important in a freshwater tank, especially when it comes to algae.

I've got a 55g which has tons of hair algae (CO2, lights, RO water, etc.) I can knock the algae down a little bit with an application of about 50 mL of 3% hydrogen peroxide. It doesn't seem to hurt the fish at this level.

Any thoughts?

mak

 

[farm41]

How much light do you have? What type co2, and what concentration is the co2? Fertilizer scheme?

RO water in a planted tank is usually unproductive, unless your water is excessively hard.

What's ORP?

 

[mak]

ORP...

First , ORP:

ORP stands for Oxidation - Reduction Potential.

(Warning warning warning I'm a chemistry professor so I tend to get a little overexcited about the chemistry in my fish tanks... :wink: )

It's easier to define what the ORP measurement is than what it measures... it's an indicator of the amount of oxidizing material (things like oxygen) vs. material that can be oxidized (ammonia, protein, general tank scum?). Kind of an inverse BOD (Biological Oxygen Demand).

ORP a important measure for saltwater tanks. In a saltwater tank, ozone may be used to increase the ORP (usually with a controller to avoid overdosing). In a marine tank, low ORP usually encourages the growth of unwanted algae.

Hydrogen peroxide, like ozone, will increase the ORP. Since the krib discusses the use of peroxide to knock down algae, I thought I'd give it a try... and started wondering if the effect was related to ORP (as it is in a marine tank). Can we learn anything from our marine colleagues?

Second (my own situation):

I've got a 55 g with CO2 (tank injection, haven't measured the concentration for a while but last time I measured it was acceptable), fertilizing with KNO3 & added Flourish & Flourish iron (Fe and NO3 I test for!). My tap water comes straight from the underground limestone bed and shows it , hence RO (plus a little added salts). I usually keep KH & GH low, below 2.

Lighting is 110W of compact flourescent + 80W regular fluorescent, which, yeah, I should change sometime soon . pH is about 5.5, which keeps the 2 pair of rams & agassizis exceptionally happy, spawning & producing offspring to take to my LFS to help finance my habit. (Only 2-3 more ram spawns raised to adulthood and I should be able to get that 125g & stand! ) I've recently reduced the tank load to only the rams + some ottos; it gives me a chance to watch the rams raise their fry.

The algae is getting better now that I've reduced the fish load & started adding peroxide from time to time. The interesting thing is that the peroxide seems to have really knocked back the black beard algae.

'Course, it could all just be reduced fish load...

mak

 

[farm41]

Could you get a current Kh and Ph levels please? Hair algae is usually a problem with low co2. What do you consider acceptable co2 levels? With your listed Kh and Ph you're not even on the co2 chart I like 20-30ppm, no hair algae. SAE is very good on the hair algae too, they will knock it down fast.

 

[fishgeek]

phosphate levels?
my last algal outbreak was i believe related to increased organic material in water coloumn, in this case the red cabomba i was watching slowly melt in the vain hope i would turn it around

increased phosphate leads to increased algae in my hands

andrew