Petromalt -- how often?

Question
Dear Sarah,
    About 18 months ago, we lost a beloved 9-pound black bunny (mostly New Zealand, I believe) due to digestive problems. So we are quite atturned now to any possible digestive problems in the two chocolate-and-white Dutch bunnies (spayed females) we got after his death.
     A couple months ago, we started seeing very small poops (perhaps 1 or 2 mm instead of larger) in the girl's pen. So we began giving them Petromalt daily (an amount about the size of toothpaste you would put on a toothbrush). To our surprise, they love the stuff, and come running for it. We are still giving it to them. Their poops returned to normal size within a month after we started them on Petromalt. The question is" is there any harm in continuing to give them Petromalt daily (other than the high cost)?

Thanks in advance for your answer.

Answer
There is no harm in it. However, I have found that plenty of hay, a bit of rolled oats each day, and a papaya tablet each day are generally more helpful in controlling ALL types of digestive problems. Petromalt only helps prevent hairballs. Rabbits generally adore papaya tablets. They will eat them up like candy. They are also usually less expensive than Petromalt, and most health food or suppliment stores (like GNC) carry them.