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Jun 15, 2005
:confused: should the octos water be set to the numbers for each thing (such as ammonia 0 ppm) said below, in other words are the amounts below correct???
Ammonia 0 ppm
Nitrite 0 ppm
Nitrate 0-5 ppm
Phosphate 0.09ppm tested with highly accurate Merck kit
pH 8.0
KH 12
S.G. 1.025
Oxygen 90%+ of Saturation level
Temperature stable at 25°C
Redox -100, Minus figure is required for correct functioning of the nitrate reactor.


Dec 22, 2004
Don't ask us: Before you can cope with the challenges of keeping an aquarium, you should know what each of those is and understand why each value is what it is.

Other than redox, that is. You shouldn't have to worry about that until college :smile:



Staff member
May 30, 2000
Dan, this is a perfectly good place to ask such questions! This is not an "experts only" forum.

To illustrate the point, I'll not provide nini with any guidance since I have no idea what the answer is. :wink:

Can anyone provide some answers here? Thanks -


Mar 14, 2006
Hope this helps

Nini, we might as well learn together here... I'm a beginner too.

Let's start with pH. pH stands for the power of Hydrogen, which basically means it is a measurement of the acidity and alkalinity levels. I'm going to quote from About.com here.
The generally accepted pH level in saltwater systems is between 7.6 and 8.4, but reef tanks are a bit more sensitive to pH and should be kept more toward higher levels. The normal trend for pH in a tank is downward, or more acidic. The additions of acids into a tank will lower the pH in the tank water. These acids come from several sources, the primary ones being: (1) excess carbon dioxide (CO2) from respiration caused by lack of sufficient gas exchange, (2) nitric acid from biological filtration (nitrification), and (3) organic acids from metabolic wastes.
Therefore, your pH level is right in the middle. I've been told that between 8.0-8.4 was good but someone may correct me here.

Decaying matter, waste from creatures in your tank, excess food, as well as water pumped through fish gills will add to ammonia in your tank. Everyone recommends that ammonia levels be zero in the tank because ammonia becomes toxic (poisonous) very quickly, especially in a saltwater environment. So CONGRATS! :rainbow: You have the right amount of ammonia in your tank - zero!

Since your ammonia, nitrite and nitrate levels are zero or near zero, you've gone through nitrogen cycling in your tank already, I presume. The nitrogen cycling process is the way to make your tank into a little ecosystem. Good job! You're doing much better than I did, when I got my octopus.

During the cycling of your tank, the ammonia will get transformed into nitrite by bacteria, which can be again toxic to creatures in your tank. But again, great! Your levels are zero.

Nitrite was needed to start off the 3rd part of the cycle. Nitrobacters are bacteria that feed on Nitrite and their waste produces Nitrate. You need nitrobacters in your tank to help get rid of the "bio-load" which are the things that create ammonia. See the cycle?

You basically want to grow this bacteria so the waste in your tank won't decompose and become ammonia. But to grow this bacteria, you needed to make your tank poisonous for a little while. So your levels are saying, you've finished the first poisonous stage (ammonia = 0), and the 2nd poisonous stage (nitrite = 0), and you are well into your third stage (nitrate = 0-5ppm).

That's about all I know. I'll do a little more research over the next few days about your other parameters and see if I can come up with some more help for you.

Hopefully, somebody with a lot more experience than I do (I've only been doing this for less than 6 months) can help you out with the rest of the information.



Staff member
Nov 20, 2002
A lot of the information you need is already in the Ceph Care articles.
This is from Colin's article, Keeping Cephalopods in Captivity, which you will find in our Ceph Care articles:

2. Water Parameters and Quality

Cephalopods have soft bodies and are essentially naked (except the nautilus that has an external shell). They have a huge surface area and therefore are very sensitive to water quality and pollutants like ammonia and nitrite, which should all be kept at zero. Nitrates seem to be tolerated to 50 - 100ppm with no apparent ill effects.
Copper is lethal and should be tested for before the octopus is added to an aquarium. Treat them like all other invertebrates in this respect.....

Salinity is the other water quality parameter that must be controlled carefully. It is of paramount importance that the octopus aquarium has full strength seawater. Aim for 1.026 at all times, a lower salinity will kill them. ....

PH must be kept between 8 and 8.4 and it is always worthwhile to do a 25% water change on a fortnightly basis. Remember they do produce a lot of waste!

These are the parameters you need to test for: salinity and PH, nitrites, nitrates and ammonia.

Some of those other parameters you mention are of more concern for reefkeepers.

Temperature will depend on the species you're keeping.

Do you have a nitrate reactor, nini?

Jan 4, 2006
Ammonia 0 ppm - Good keep it here, if it goes any higher it means that your filter is not capable of handling the bio load put on it. It also means to watch for a Nitrite spike in a couple of days. Nitrite is even more lethal to cephs that ammonia.

Nitrite 0 ppm - Good again. Stage 2 of the nitrogen cycle needs to be zero.

Nitrate 0-5 ppm Good, but will rise as the filter processes waste material, and is lowered by water changes and denitrators. Nitrate amounts are decreased by use of a protein skimmer.

Phosphate 0.09ppm tested with highly accurate Merck kit - This is a helper with nitrates to make the algae blooms in your tank. Doesn't really effect ceph husbandry.

pH 8.0 -should be a little higher for standard reef keeping like was said before, but you aren't reef keeping.

KH 12 -Carbonate Hardness of water. Used to measure amount of usable calcium for stony corals and clams. Not needed for octos.

S.G. 1.025 -shoot for 1.026, but this will change with evaporation, skimmer production, etc.

Oxygen 90%+ of Saturation level - Keep oxygen as high as possible with a protein skimmer and good water movment. I don't have a test for this in my own setup, but if you have the test-more power to 'ya. More oxygen and flow the better.

Temperature stable at 25°C - 77 deg F is okay for tropical cephs, temperate need lower.

Redox -100, Minus figure is required for correct functioning of the nitrate reactor.- the technical version is "The redox potential of an aquarium is a measure of the aquarium water's ability to cleanse itself."- I understand it to mean you use that number with ozone to be sure you don't kill everything in the tank while you are trying to help it. I don't know if that number is good or bad.

Just my 2 cents...


Jun 15, 2005
thanks for the advice =) as far as my tank set up, i dont have anything but 10 galllons of water in it but im going to be adding live sand and live rock. whats a nitrate reactor? i prolly need to get one. and how often do i need to change the water?
thanks alot!


Jun 15, 2005
oh and just so there is no confusion the amounts ph,nitrite,amonia, and all of those arent my amonts, they are just amounts that i wanted to make sure were correct for my aquireum once i got it up and running. i dont even have all 55gallons in the tank yet :/

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