how often to change substrate?

[dorian965]

i bought a new tank that has been set up for about 4-5 years and when i moved it i noticed that the sand looked really bad. its a fine sand and it was stired up really bad when i moved. the water was very dirty in the tank when i filled it up and i added about half fresh saltwater to the system (30 gallon).

i have sence run all test that i have on the tank and the water is great.
am. 0
trite. 0
trate. 5
ph. 8.3
alk. 3.1 a little high
i havent tested the calcium yet, i ran out of the test kit.

i noticed the there are tons of worms in the sand and rock. lots of tiny white worms, and was wondering if i should replace the sand and lose all my life in it or should i be ok. the sand bed is about 2 inches thick.i also didnt know if i should add nassarius to turn the sand . i was afraid that it might stir up some problems. thanks dorian

 

[seaham358]

I would have changed out the sand before setting the tank back up. A 4-5 year old SB that is tossed about may have released excess nutirents back into the tank. I had my SB in my fuge crash in around 2 years, it smelled like rotten eggs.

The worms can be saved, all you need to do is pick them out.. It will take some time but saving some will make sure that are some to repopulate the tank.
Adding snails is ok, at this point from what I understand it has been sturred up alot and has settled down so the snails won't hurt anything now.. JMO

the tank looks nice...

 

[tecwzrd]

IMO I think it would be too much effort. Plus the bacteria/life lost from doing so would be more detrimental then just doing it to have “pretty sand”

Beautiful tank by the way From the photo it appears to be a 55 gal with about 2”-3” sand bed and to me it doesn’t look dirty at all. Quite what I’d expect from a 4+ year old tank.

Adding 15 or so (depending on how many you have now) nassarius snails would help keep the sand bed stirred and considering the depth of the sand it shouldn’t be an issue.

 

[melosu58]

That`s a nice tank you bought there. Since you already put the tank back I would not change it now. I agree that tec had a good idea in putting the narsaris snails and maybe even a sand sifter star or goby.

 

[dorian965]

thanks guys, the tank is a 30 gallon and i have to move it again next week. i know it really stinks to move the system twice in 3 weeks but i have no choice. the reason i asked is that i could replace the sand when i move it again. i wouldnt worry but since i set it up i have noticed some grey spots apearing in the sand bed. ill post some pics later.

thanks for the nice words and the help.i paid a little more than i wanted to but i got enough coral growth that it made up for it. nice sive brain, 4 head branching frogspawn and some cool xenia.

 

[ellisz]

I have heard opinions on both sides. I moved my tank last year and the sand bed was was about 2 years old. I separated the top layer and the bottom layer and then put the sand back in since it smelled fine. I use nassarius snails to keep the sand bed turned over.

If it smells bad then don't use it. Worst case though you could keep a few inches of the top layer and then replace the rest.

 

[cmor1701d]

keep a few inches of the top layer and then replace the rest.

That sounds like good advice as the top 2" or so is where most of the bacteria and beneficial critters live. A 2" sand bed is not deep enough for denitrification and is considered a SSB (shallow sand bed). You could also keep half and mix in some new sand

Seaham, how deep was the sb in the fuge and what are the fuge dimensions?

I have a DSB in my main (6"-8") and have not had any problems in the 3 years it's been running. I have heard of crashes in the 5 year+ range but I have been unable to confirm that from anyone who has had a large DSB crash.

 

[tecwzrd]

A 2" sand bed is not deep enough for denitrification and is considered a SSB (shallow sand bed).

Just to clarify, I thought if fine grained aragonite sand was used that 2” is deep enough for denitrification. Particle size plays an important factor as well.

 

[cmor1701d]

Check out An Introduction to Deep Sand Beds by Anthony Calfo...

"Many theories and recommendations abound as to how best NNR can be achieved. We do know that good denitrification is less likely (but not impossible) to occur in shallow sand beds (less than 3?/7.5 cm), and with course sand. Some of the difficulties and criticisms of failed DSBs may be fairly attributed to such intermediate sand depths (1-3?/25-75mm) where the substrate was neither deep enough for efficient denitrification, nor shallow enough for thorough nitrifying activities. This condition is mitigated by the all too common lack of adequate water flow in some marine aquaria. Strong water flow is critical in most any marine aquarium. Aspire to provide at least 10 to 20 times the tank?s total volume per hour in water flow for your aquarium. The ocean is a dynamic environment! When nitrate control is your primary ambition, use deep fine beds of sand. Smaller aquaria (under 75 gallons) should employ at least 3? of media; larger aquaria will benefit from 6? (15 cm) or more. "

Most everything I have read says a DSB starts at 4" and anything less should be considered a SSB.

 

[tecwzrd]

Most everything I have read says a DSB starts at 4" and anything less should be considered a SSB.

Thanks for the link, I’ve read that one and ”How Sand Beds REALLY Work” by Ronald L. Shimek, Ph. D.

Agreed that a DSB starts at 4+”. Denitrification can still occur in SSB particularly if finer sand is used and is the only point I was making.

A deeper sand bed provides a better environment for oxygen deprived bacteria which converts the no3 to nitrogen but also creates a greater risk for crashing.

I keep mine at 3”-4”.

 

[dorian965]

heres some pics. the sand got all stired up when i moved it and i didnt notice these dark spots until a couple of days later. it just looks bad and i was concerned what the problems could be. i also noticed some sand that had turned greyish blask under some rocks as i was tearing it down and thought it may be a concern as well. i really dont know much about fine sand. i have used a more corse form of argonite.