old tank syndrome

[dnsfpl]

my total water volume is app 400l
doing weekly water change(20l, 5%) for the past 2.5 years, using tap water with anti-chlorine
thinking of doing a major water change(100l, 25%), using rodi water

does major water change prevent old tank syndrome?
will major water change bring more harm than good?

thanks

[MrClam]

Hard to say, as old tank syndrome is somewhat of a third rail in reefing. Some people claim it as myth, others swear any tank with sand has an expiration date.

I've yet to hear anyone say miderate waterchanges are harmful though, so can't hurt to try. I'd also turkey baste rocks and siphon sand a bit at a time if your trying to avoid ots

[dnsfpl]

objective is to reduce accumulation of chloride, heavy metal, etc and also to replenish elements

my main concern is will major water change bring more harm than good?

cheers

[Uglyman]

Whats the TDS of your local tap water? also using dechlorinators only bind up the chlorine they don't remove it so it stays in the system and is only removed when you do water changes and if not enough water is changed they will build up.
Also you are not removing anything else from the tap water which includes Po4, No3 and heavy metals which are not good for your marine life. It cannot be said enough in this hobby but a RO/DI unit IS A MUST HAVE ITEM for a reef tank unless you go with NSW.

A large water change will do minimal good if you are still using tap water, if you do a change using RO/DI water and a good quality ASW then things will change for the better.

[dnsfpl]

tap TDS app 60

any method to make rodi water without rodi unit?
iirc someone make rodi water using pump and di resin

cheers

[dnsfpl]

bump

[crsswift70]

DI resin alone will not make the water you need. You need the other filters to actually take out the particles and impurities.

[Timfish]

One 25% water change will not prevent or cure old tank syndrome. For a better description od old tank syndrome read Julian Sprung's article here: http://www.advancedaquarist.com/2006/10/aafeature

You didn't say what your pH, alk and calcium levels are and what they have been in the past. Many of us use the ol' eyeball test (myself included) but keeping some record will warn of potential problems developing when one or more start trending downward. Another indicator is a gradual increase on phosphates. (I never test for nitrates or nitrites but some people monitor that as well.)

I do not have a problem with using tap water here in Austin and we have pretty high TDS but it's mostly calcium carbonate. If you are going to be doing multiple large water changes I would at least run the water through a carbon filter. Keep in mind with RO and RO/DI does not remove the ammonia from chloramines so if you test new saltwater or aquarium water less than a day after a big water change you should see some ammonia. Here's a 240 gallon system which for the last 5 1/2 years has been getting 15 to 20 gallons of top off water along with a 20 gallon water change every 10 - 11 days so I would worry about a 25% water change unless you have heavy metals in your local tap water.

http://www.youtube.com/watch?v=GFxUSRFRp24