Zero Nitrates, Water Changes.......Why?

[Bderick67]

Currently the 450g with aro gets a WC every week of 35-50% the nitrates are in what looks to be the 10-15 ppm range. A couple weeks ago I went two weeks without a WC and the nitrates were at 20ppm. My aros and other fish always seem a little more lively after WCs(of coarse this could also be just because the tank if filled back up). Though I can't say there was a major change in behavior when they went two weeks between WCs.

The origin of this thread has more to do with when I build a 700g pond/tank in my basement. I have been considering linking the 450g and the pond together and adding hydroponics to the mix. IDK just some thoughts that I would like to get opinions and answer to.

 

[David R]

Yeah, don't think I'll ever get rid of WCs, especially in the summer when I gotta water the flowers and lawn anyways. Why not use the tank water for that and replace with fresh water.

That's my plan too, though the fruit trees and vege garden are above the level of where the tank is, so I'm going to have to invest in a storage/pump set up.

I'd be interested in using the tank water for hydroponics too, not sure if the extra power consumption from heat loss would make it worth while.

Sent from my HTC Desire HD A9191 using MonsterAquariaNetwork App

 

[pk705]

The extra activity after a wc might be due to a temperature change? (freshwater with a different composition, temperature, oxygen content seems a lot like rainfall to me).

If worried about extra consumption due to heat loss, you could always keep plants paludarium style.

 

[guano]

Since hydroponics came up, is there any ill effects using Safe/Prime treated water on fruits and vegetables that you plan on eating? My wife puts some green onions in a glass and some tap water and leaves them on the windowsill. She cuts what she needs and a few days later produces more leaves. I was thinking about using them. Love to have plants that help filter and then eat them too.

 

[Bderick67]

Since hydroponics came up, is there any ill effects using Safe/Prime treated water on fruits and vegetables that you plan on eating? My wife puts some green onions in a glass and some tap water and leaves them on the windowsill. She cuts what she needs and a few days later produces more leaves. I was thinking about using them. Love to have plants that help filter and then eat them too.

Good question, prime states that it is not for human consumption. I plan on not eating any of the veggies produced at first, would eventually like to do tomatoes if all goes well.

 

[cjack]

So, I was taught that the reason you can't have a full sized goldfish in a bowl (even with the Nitrates and other nitrogenous wastes at 0) is because the fish releases hormones that inhibit the growth and effect the internal functions of the fish. I took a quick look at some studies and found that there are indeed hormones that are released across the gills of all fish that effect the internal functions of fish (developmental, reproductive, osmoreguative, and others). So, while you wouldn't need to do water changes for the nitrogenous wastes, there are hormones that need to be removed. You will also have to replace the minerals that the fish take in (like others have said), I would venture a guess you could get by with an incredibly varied diet, but there are likely still some that just aren't going to be available. Then there is the issue with oxygen and CO2. While live plants will take care of the CO2 issue during the day, there is still the issue of pH over the long term because CO2 reacts with water to form carbonic acid, leading to a lower pH which will be a problem at some point. So, you will have to be buffering your tank so counter the acidification.

As far as the freshwater skimmer goes, I assume it could work with an intense amount of aeration (as duanes said). But that won't help with any minerals lost to the fish/plants/bacteria, and will probably not have any effect on the hormones in the water. The use of ozone would be great for sterilizing the water, but again, not so much in terms of neutralizing the hormones.

 

[Drstrangelove]

"there are indeed hormones that are released across the gills of all fish that effect the internal functions of fish (developmental, reproductive, osmoreguative, and others)"

Can you post a link to that? I've been looking for that and failed at finding anything like that.

 

[cjack]

Yeah, no worries.

http://joe.endocrinology-journals.org/content/214/3/409.full
http://ehis.ebscohost.com/eds/detai...c2NvcGU9c2l0ZQ==#db=edswsc&AN=000309784400001 - sorry, not a full article, but its the best i could find right now

http://ehis.ebscohost.com/eds/detai...NvcGU9c2l0ZQ==#db=edselp&AN=S0016648012003747 - again, not a full article, but you get the idea
http://lifes.nchu.edu.tw/upload/publish/2011830235013\2011AJP_Review.pdf
http://www.panamjas.org/pdf_artigos/PANAMJAS_4(2)_158-178.pdf

 

[pk705]

Ozone is one of the most powerful oxidizing agents, I don't see how it wouldn't be able to react with relatively large molecules in a sufficient manner to stop them from being biologically active. (certainly it would be able to oxidize the double bond in cortisol).
http://en.wikipedia.org/wiki/Ozone#Reactions
I skimmed over the abstracts of the last four links - I haven't found an instance of actively secreting hormones into the water with the purpose of communication/growth control.

 

[duanes]

Fractionation/protein skimming can remove many of the things spoken about above, anything from free floating algae and parasitic micro animals, oils, to medications (dissolved metals such as malachite) this is why it is recommended they be turned off during treatment, or proteins (hormones, amino acids etc).
Some users of fractionation use ozone as an agitator, but unless totally used up by organics can carry over into the tank and have deleterious effects.
Ozone has a half life of 15 minutes in water, and most aquarists don't have a 15 minute turn around time to use it up before reentering the tank with fish. 4ppm ozone can destroy human lung tissue.
I did lab comparisons of straight tank water, to fresh water fractionator waste and found after dessication the dissolved solids in fractionator waste to be 7-10 times heavier the straight tank water. Waste water left/tank right