Upcoming article possibility: what chemistry is different in marine vs fresh?

Randy Holmes-Farley

Reef Chemist
Premium Member
Many of the people who get into reef keeping started with fresh water systems at some point.

They learned some chemistry there, and much of it may be useful in reef keeping.

But some doesn't extrapolate well, and I'm thinking of putting a summary of them into a single article:

Important chemistry differences between marine and freshwater aquaria

So I need to compile a list of the differences.

Some are:

Nitrite toxicity
ammonia speciation (NH3 vs NH4+)
need to put anything into RO/DI water
general hardness
test kit differences
Skimming effectiveness
ozone reactions
baking soda effect on pH
calcium carbonate substrates impacting buffering and pH

what are some others?

TIA
 

Habib

CEO of Salifert
Premium Member
Other quality requirements for activated carbon if used in reef aquaria.
 

Habib

CEO of Salifert
Premium Member
Use of old tank for marine/reef aquarium if meds (e.g. copper containing) were used.
 

bertoni

Premium Member
Frequency of calcium and alkalinity supplementation seems to come as a surprise to a lot of people.

Issues with bio-balls, bio-wheels and nitrate accumulation. I guess that's getting into filtration.

Water oxygen content. I don't run FW (haven't in a long time), but FW seems to hold more oxygen, or so it would seem from some stocking lists. Maybe that's aggression, though?
 

Randy Holmes-Farley

Reef Chemist
Premium Member
Great, thanks guys.

Phosphate fertilization

Meaning it is "needed" in planted tanks?

I know people often use phosphate buffers.

Is the primary difference the concern that phosphate inhibits calcification in seawater?

Algae problems would presumably be similar.

What normally limits algae growth in freshwater systems? CO2? nutrients? iron?

TIA
 

speakerguy

Premium Member
What normally limits algae growth in freshwater systems? CO2? nutrients? iron?

I always just thought saltwater algae was just more 'evil' than FW algae; also they are not lighting their tanks with a thousand watts of halides :) PC lights seem to be more than plenty for even the best of FW planted tanks.
 

bertoni

Premium Member
I think I see more issues of poisons, venoms, toxins, etc with reef tanks. Palythoa comes to mind.

More random thoughts. :)
 

speakerguy

Premium Member
Ooh! Calcium precipitation. Those freshwater dudes have probably never cleaned a powerhead/pump in their lives.

Also agree with metal parts incompatibility. Lots of stainless steel FW equipment out there.
 

bertoni

Premium Member
They probably haven't had to pay much attention to evaporation, either, although that might be pretty obvious.
 

Boomer

Bomb Technician (EOD)
Premium Member
Yes, Jon water getting so hard you can bounce a bowling ball of it.



CO2 levels FW vs SW

Shift in activity( coefficient) FW vs SW...why more can be dissolved in SW vs FW

Shift in pka's

Sun is not good for FW tank, makes algae go nuts. Green water much, much, more common in FW

Undergravel filters

Varity of algaes, very limitted in FW. FW tanks usually have "plants"

Direct CO2 injection common in FW planted, no media

Dentrification is about 0

What lives in the substrate and its diversity

Bubble formation and surface tension, to include skimming ( ok you have that)

Available live food, living in the water or substrate

Some people think you do not need an Alk kit in FW as they think pH is the same thing as Alk :D

Cable heaters in the substrate or under the tank in FW

Adding shells and gypsum in FW for decoration, not a good idea .

Diseaes are more common in SW and a much greater variety.


Chillers common on reef tanks

Randy

I know people often use phosphate buffers.

But not for fert..just to buffer the water. Most of the time that buffer is just plain sodium biophosphate

Most FW planted tank guys are worried about iron and CO2
 

Habib

CEO of Salifert
Premium Member
Phosphate fertilization

Meaning it is "needed" in planted tanks?

Phosphate is often a nutrient used (knowingly or unknowingly) for planted tanks. Something which should normally not be added in reef tanks.

Also many buffers for freswater application contain large amounts of phosphate. I have seen a few cases in which someone used such a buffer in a reeftank.
 

Habib

CEO of Salifert
Premium Member
Just saw KaBooms comment:

But not for fert..just to buffer the water.

Several plant grow supplements for freshwater aquaria do contain phosphate.
 

Randy Holmes-Farley

Reef Chemist
Premium Member
Great, everyone,thanks.

Certainly too much for a single article, but a subset of it might make a nice one. :)

I'll probably be coming back for more info as I'm not up to date of freshwater issues. :)
 

DrBDC

New member
FWIW we raise applesnails. Pomacea bridgsii if that matters. I treat it like a saltwater tank in many ways. I shoot for about 6-8 dKh and at least 9 on the GH. This did not work very well when I tried to make a heavy planted tank using a diy co2 system due to the hardness/pH/CO2 balance issues and I had mantle issues with the snails. At times I've used kalk even for some evaporation since the snails need the same basic calcification minerals as in a reef. For the snails they like close to 8.0 pH. Very similar I believe to many of the cichlids. In fact I use your 2 part when I see the dKh drop any.

I used to use ro rite to correct the ro/di water but as of the last few months I've been using my ro/di waste water. I think that the freshwater species are more dependant on the calcium in the diet vs just the water column but that is something for the invertabratologists. Is that a word? Just some freshwater misc. rambling. :D
 

Boomer

Bomb Technician (EOD)
Premium Member
Hab

Just saw KaBooms comment


That use to be my old screen name and people kept calling me Boomer, to shorten it, so I changed it. Now I have allot of you guys are calling me Boom....no I'm not chaning it again, as I will then end getting called Boo or Bo :lol:
 
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