Dumb water change question

[Ethreal]

Sorry if this has been asked a million times but I couldnt find a definitive answer.

Advice on this site seems to suggest a pwc of 10-15% per week at least in the early days.

I got to wondering if this means.........

1. 10-15% is the bare minimum you should do to keep your tank healthy, but you could change upto ??% and that would be great because???

2. you should never change more than 10-15%, if you do there are dire consequences that are???

Many thanks for taking time to read this.

 

[Hubert90]

Sorry if this has been asked a million times but I couldnt find a definitive answer.

Advice on this site seems to suggest a pwc of 10-15% per week at least in the early days.

I got to wondering if this means.........

1. 10-15% is the bare minimum you should do to keep your tank healthy, but you could change upto ??% and that would be great because???

2. you should never change more than 10-15%, if you do there are dire consequences that are???

Many thanks for taking time to read this.

Well that really depends if u are overstocked and wat filter u have.

 

[Ethreal]

Thanks for the quick response. Water change has been done every 7 days. The tank is an Orca TL550 (128 litres) and I have been changing 20 litres per week, so just a little over 15%.

• 128 Litres/28 Gallons
• L570mm x W510mm x H670mm
• 2 x 24w T5 Compact lights + Cooling fans + Moonlight LEDs
• 720lph Return Pump
• Skimmer
• Heater
• UV Steriliser

I replaced the plastic balls with LR rubble and added another ph otherwise the setup is as above.

Stock is

2 x Tangerine Clowns
1 x Flame Angel
2 x Trochus Snail
1 x Orange spot snail
2 x cleaner shrimp
4 x soft corals
30lb LR + LR rubble in the filter.

I use RO water from the LFS.

Amonia = 0
Nitrite = 0
Nitrate = 12.5ppm - This never seems to reduce following a water change.

 

[carey]

I do at least a 20% pwc every week on all my tanks. I've just managed to get my nitrates down to 0 after many months of trying.

Do you find your skimmer getting anything good? It's supposed to remove organic particles which I think would be very helpful on top of the water changes.

 

[Ethreal]

Carey thanks for the reply, the skimmer is full of yucky water and particles and I empty it each morning.

I will up my pwc to 20% - at the moment I just dont see any reduction in nitrate pre and post pwc, I guess it could be that a 15% reduction in 12.5ppm is just too small to register on my test kit using red sea marine labs or tetra for nitrate testing = poor choice perhaps.

 

[carey]

I use salifert tests for my nitrate, very very accurate and goes down to like .10 or something silly like that . LOL

I would bet you'll see some reduction if you up the % of pwc. Youre probably right about the concentration.

 

[HN1]

All good advice, though each tank is different. That's why testing your tank often and knowing exactly what goes into it is important. Journaling even.

I would caution you on the flame angel. IME, they need a tank with more swimming room. Also, I've never seen an old reef safe angel. They all seem to turn suddenly one day. Watch for your zoas to stay closed more often.

 

[melosu58]

I've never seen an old reef safe angel. They all seem to turn suddenly one day. Watch for your zoas to stay closed more often.

You are right about that. Mine went 4 yrs before it started munching.

 

[RYANLAWRENCE]

You just need to watch your water quality. If nitrates get 15 or greater i normally end up doing a change (about every week and a half for me). If you have a reef tank you would want nitrates to be as low as possible i just have FOWLR

 

[RYANLAWRENCE]

And dont think that asking a question is dumb! the people on this forum want to help and see you succeed in the hobby!

 

[Ricksreef]

Didn't notice in the thread,how much of a sand bed and how much live rock do you have?

 

[Ethreal]

HN1 - thanks for the really useful info on the flame angel, we are starting a larger tank within a couple of weeks, so the angel will be moved when that has fully cycled.

In terms of testing, I may be over cautious, but I test for amonia, nitrite, nitrate, pH, alk and sg each day and do keep a journal of the results and any changes I have made.

Ricksreef - Sand is around 2" deep, feel free to give any advice here, since the lfs said it didnt matter how deep the sand was as long as it provided a base for the LR. LR is around 30lb which includes 1lb of LR rubble.

Carey - I will try out Salifert test, thanks.

Ryanlawrence - I do a water change every 7 days, I just dont seem to see a reduction in nitrates after the change.

 

[Ricksreef]

IMO You need a little more LR,to increase the amount to one and a half to two lbs per gallon.Also I would slowly increase the sand bed until you have at least four inches,that allows for the different levels of nitrifying bacteria to do their thing.I would get the cheaper base rock to add,it will become live very quickly and you won't have to worry about a new cycle possibly starting.

Always remember to take LFS advice with a grain of salt if it is one of the chain stores as their employees only know what they read in the employee handbook.Try to find a close LFS that is Saltwater only and has been in business awhile if you can.

 

[boardsurfer]

There are a lot of variables considering how often or how much % pwc you should do, but I typically do a 15-20% pwc.

 

[Ethreal]

Ricksreef, again thankyou for your response, I have some more LR reserved for me at the lfs, he wont let me have it yet until he has 'cured it, tested it and restested it', so your advice is great, Im slowly increasing my stock of LR.

The depth of sandbed is really interesting, makes sense what you say - another stupid question perhaps, but, do you ever, ever turn over/disturb your sandbed or do you just leave it to the snails? If you leave it to the snails - how many snails for a 4"deep sandbed on a 128ltr tank?

Boardsurfer, thanks for the response I'm feeling comfortable about increasing pwc weekly from 15 to 20%, good to know that the 10-15% doesnt represent the absolute maximum that could be changed.

 

[Ricksreef]

Your welcome.
No I don't ever turn the sand bed over.Would just start out with a couple Nassarius snails for your size tank and see how it goes.The best livestock you could get is the Diamond Goby.He will keep your sand bed really looking nice plus he is so fun to watch.

 

[Ethreal]

thankyou Ricksreef, good advice.

 

[Ethreal]

Nitrate test.

So this has been really bugging me - ie the non reduction of nitrate readings despite pwc (discussed in another post), so I did a little experiment last night.

Using Tetra test kit for NO-3.

A. Following the instructions to the absolute letter, added reagent 1, reagent 2, added zinc powder and shook for 20 seconds, added reagent 3 - let it stand for 10 minutes.

Result = 25ppm

Observations - it was clear that the zinc powder had not fully dispersed within the reagents during the 20 seconds of shaking.

B. Following the instructions as above BUT after adding the zinc powder I deviated and shook the tube until my arm fell off and the zinc powder was fully disolved 1.5 minutes in total, then continued as per test instructions.

Result = <12.5ppm (closer to zero than 12.5ppm)

Observation - The zinc powder was fully dispersed in this test - as intended by the test manufacturer.

I cant be sure what is responsible for the change in result

1. Full dispersal of zinc powder or

2. Increased time between commencement of test and test result reading (an additional 1 minute and 10 seconds)

but....... I suspect that failure of the zinc powder to fully enter solution may be giving a false positive result in nitrate testing.

I have emailed tetra to ask more details of just what is in there tests and what effect the above test observations might make on the results, will let you know if they respond.

Really interested to hear anyone elses view.

 

[Smitty]

Can I recommend you get a different test kit? I have been using API in my FW tank and only have to add the drops, never any kind of powder, and it seems to work really well. Plus having a different test kit may help see if your current one is accurate or not.

 

[Ethreal]

Thanks smitty, yes I'm definately going to buy another test kit, this is the second brand I used, first being red sea marine lab, some issues with that brand also.